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  TEXAS AGRICULTURAL rxrmmsnr smmu

B. YOUNGBLOOD, DIRECTOR
COLLEGE STATION, BRAZOS COUNTY, TEXAS

BULLETIN N0. 347 . APRIL, 1927

DIVISION OF ENTOMOLOGY

STUDIES AoN THE BIOLOGY OF
THE PECAN NUT CASE
BEARER

AGRIOUL  & fifififiAlqlgAL
COLLEGE 0F TEXAS LIBRARY

 

AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS
T. O. WALTON, President

STATION STAFFT

ADMINISTRATION: '. _

*8. YOUNGBLOOD, M. S., Ph. D.,_ Director

A. B. CoNNER, M. S., Acting Director

R. E. KARPEH, B. S., Acting Vice-Director
J. M. SCHAEDEL, Secretarg
M. P. HOLLEMAN, JR., Chief Clerk
J. K. FRANCKLOW, Assistant Chief Clerk
CHESTER Hmcs, Executive Assistant
C. B. NEBLETTE, Technical Assistant

VETERINARY SCIENCE: _
**M. FRANcIS, D. V. M., Chief_ '
H. SCHMIDT, D. V. M., Veterinarian
J. D. J0NEs, D. V. M., Veterinarian ,
CHEMISTRY: _ _
G. S. FHAPS, Ph. D., Chief; State Chernist
S. E. AsBuRY, M. S., Assistant Chemist
WALD0 H. WALKER, Assistant Chemist
VELMA GRAHAM, Assistant Chemist
ADAr-r E. STURGIS, B. S., Assistant Chemist
E. C. CARLYLE, B. S., Assistant Chemist
R. O. BROOKE. M. S., Assistant Chemist
T. L. OGIER, B. S._, Assistant Chemist
J. G. EVANS, Assistant Chemist
I-IORTICULTURE: _
W. B. LANHAM, ‘M. A., Chief
H. NEss, M. S., Berry Breeder
RANGE ANIMAL I-IUSBANDRY:
J. M. JoNEs, A. M., Chief; Sheep and Goat
Investigations
J. L. LusR, Ph. D_., Animal Husbandman;
Breeding Investigations
W. H. DAMERoN, B. S., Wool Grader
ENTOMOLOGY:
F. L. TiioMAs, Ph. D., Chief; Slate
Entomologist
H. J. REINRARD, B. S., Entomologist
W. L. OWEN, JR., . S., Entomologist
S. E. McGREGoR, JR., Acting Chief Foulbrood
Inspector
GrLLis GRAHAM, Foulbrood Inspector
OTTO IVIACKENSEN, Foulbrood Inspector
AGRONOMY:
. B. REYNoLns, M. S., Chief _ _
. B. CoNNER, M. S., Agronomist, Grain
Sorghum Research _
KARPEB, B. S., Agronomist, Small
Grain Research _
. C. IVIANGELSDORF, Sc. D., Agronomist;
Corn and Small Grain Investigations
. T. KILLOUGH, M. S., Agronamist, Cotton
Breeding _ _
. C. CUSHING, B. S., Assistant in Crops

ratings»:

SUBSTATIONS

No. 1, Beeville, Bee County:
R. A. HALL, B. S., Superintendent

No. 2, Troup, Smith County:
W. S. HOTCHKISS, Superintendent

No. 3, Angleton, Brazoria County:
R. H. STANSEL, M. S., Superintendent

No. 4, Beaumont, Jefierson County:
R H. WYCHE, B. S., Superintendent

No. 5, Temple, Bell County:
H. E. REA, B. S., Superintendent

No. 6, Denton, Denton County:
P. B. DUNKLE, B. S., Superintendent

No. 7, Spur, Dickens County: _
R. E. DICKSON, B. S., Superintendent

No. 8, Lubbock, Lubbock County:
D. L. JoNEs, Superintendent
FRANK GAiNEs, Irrigationist and Forest
Nursergman

No. 9, Balmorhea, Reeves County:
J. J. BAYLEs, B. S., Superintendent

Teachers in the School of Agriculture Carrying Cooperative Projects on the Silt! »
AnRiANcE, M. S., Associate Professor of Horticulture

., Professor of Entomology

GROUT, M. S., Professor of Dairy_ Husbandry

. W.
.  BILSING, Ph. D
'P.'

LEE, Ph

— 1A5 of April 1, 1927.
*On Leave. _ 
**Dean, School of Veterinary Medicine.

***In cooperation with U. S. Department of Agriculture.
****In cooperation with the School of Agriculture.

 

' FARM AND RANCH ECONOMI

v ***'-I‘. L. GASTON, JR., B. S., Assist
'_ ***J. N. TATE, B. S., Assistant, Ran
SOIL .
‘***

G
V . D., Professor of M arlceting and Finance

D. ScoATEs, A. E., Professor of Agricultural Engineering _ _
H. P. SMITH, B. S., Associate Pr essor of Agricultural Engineering

  
  
     
 
   
    
  
    
  
   
 
 
 
 
 
   
  
  
  
  
    
   
   
  
  
  
  
  
   
   
   
   
 
  
  
 
  

PLANT PATHOLOGY AND PHY V‘
J. J. TAUBENHAUS, Ph. D., Chief

L. P. GABEARn, M. S., Chief
*B. YOUNGBLOOD, ., P . ., i
Ranch Economist 
G. L. CRAwEoRn, M. S.,Markett '

Specialist _
L. CORY, M. S., Grazing Rese

Records and Accounts

and Accounts

SURVEY: _
W. T. CARTER, B. _S., Chief
H. W. HAWKER, Soil Suruegor
E. H. TEMPLIN, B. S., Sail Szirvego
T. C. REITCI-I, B. S., Soil Surveyor

BOTANY:
H. NEss, M. s., Chief

PUBLICATIONS:
A. D. JACKSON, Chief

SWINE HUSBANDRY:
FRED HALE, M. S., Chief

DAIRY HUSBANDRYHH
—————————, ie

POULTRY HUSBANDRY:
R. M. SHERWOOD, M. S., Chief

RURAL HOME RESEARCH:
JEssiE WHITACRE, Ph. D., Chief

****AGRICULTUIRAL ENGINEER]

MAIN STATION FARM:
G. T. McNEss, Superintendent

APICULTURAL RESEARCH LABO
(San Antonio) ' - ‘

H. B. PARxs, B. S., Apiculturist in t4
A. H. ALEx, B. S., Queen Breeder

FEED CONTROL SERVICE:
F. D. FULLER, M. S., Chief
S D. PEARcE, Secretary
J . H. ROGERS, Feed Inspector
W. H. W000, Feed Inspector
K. L. KIRKLAND, B. S., Feed Inspect
W. D. NORTHCUTI‘, JR., B. S., Feed 1,
E. H. GARRETT, Feed Inspecto ‘

No. l0, Feeding and Breedlnl St!
College Station, Brazos Count
SiiERwoon, M. S., Anima i

man in Charge of Farm ,

L. J . McCALL, Farm Superintendent.

No. 11, Nacogdoches, Nacogdochel
H. F. MoRRis, M. S., Superintend i

***No. 12, Chillicothe, I-Iardernan C
J. R. QUINBY, B. S., Superintendent.
***JosEi>i»1 C. STEPHENS, M. A., Juni
Agronomist

No. 14, Sonora, Sutton-Edwards C0!
E. W. Ti-ioiviAs, B. S., Superintend
W. L. BLACK, D. V. M., Veterinari
V. L. CORY, M. S., Grazing Researc .

***O. G. BABcocK, B. S., Collabor i.

Entomologist
O. L. CARPENTER, Shepherd

No. 15, Weslnco, Hidalgo County:
W. H. FRIEND, B. S., Superintendent?
M. IVICPHAIL, B. S., Entomologist

No. 16, Iowa Park, Wichita County:
E. J. WiLsoN, B. S., Superintendent '

SYNOPSIS

This Bulletin summarizes six years of observations on the life history
0f the pecan nut case bearer and also contains a study of the anatomical
characters which ditferentiate it from other closely related insects, deal-
ing more particularly with the biology of the insect than does Bulletin
No. 328 of this Station.

There were four generations of this insect in 1919, 1921, and 1923.
In 1918, 1920, and 1922 there were but two generations.

The winter is passed in a tough silken hibernaculum attached to buds
on the trees. At the approach of spring the larvae begin feeding on the
buds to which these hibernacula are attached. Later they desert the
hibernacula and enter the new tender growth at the juncture of leaf
stems and make burrows, in which they pupate after attaining their
growth. The duration of the pupal period and the time the spring-brood
moths emerge is dependent largely on the temperature. When the mean
temperature was low during the month of March, the larvae did not
leave their hibernacula until early in April, but in years when the mean
temperature was high enough to start tree growth before the 20th. of
March they began feeding prior to that time. If a period of high tem-
perature was followed by a period of lower temperatures, larval and
pupal development was retarded and the average duration of the pupal
stage was greatly lengthened. This had an effect on the number ofthe
insects in the succeeding generations. When low temperatures in March
were followed by high temperatures in April, the pupal stage was short-
ened and there were a considerable number of moths emerging daily
during the period over which emergence occurred. The moths emerged
at night and, on the fourth or fifth night after they emerged, began to
deposit eggs on the nuts when the latter were about the size of English
peas.

These eggs hatch in about five days, and after feeding on the buds
immediately below the nut clusters for about two days the larvae enter
the nuts at their bases by cutting circular holes. The pupal stage is
passed within the larval burrow and lasts about nine days. The first
generation moths emerge during the latter part of May and the early
part of June. Oviposition begins on the third or fourth night after
emergence.

The eggs hatch in four days and the larvae enter the nuts as in the
preceding generation.

After completing their development they pupate within the larval
burrow. The moths of the second generation emerge betwen July 22
and September 7, depositing their eggs in grooves at the tips and bases
of the nuts or 0n buds below the nut clusters.

It requires about four days for the eggs of the third generation to
hatch. The larvae feed within the nuts as in the two preceding genera-
tions, or on the interior of the shucks, or on the shucks where two or
three nuts touch at their bases. The moths of the third generation
emerge principally during the month of September, but emergence con-
tinues sometimes as late as the 25th. of October, oviposition occurring
from four to nine days after emergence.

The eggs of the fourth generation hatch in from five to nine days,
after which the young larvae feed on shucks or at the bases of the leaf
petioles and later spin their overwintering hibernacula.

' Bibliography . . . . . . . . . . . . . . . , . . . , . . . . . . . . I . . . . . . . . . . . . . . . . .

CONTENTS

  
   
     
  
   
  
   
   
    
      
  
  

Synopsis ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Introduction . . . . . . . . . . K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Description of the Insect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Adult . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Egg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Larva . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Pupa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Original Description . .  . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. "

Life History Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Temperature Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

Spring Brood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Larvae of the Spring Brood . . . . . . . . . . . . . . . . . . . .. - . .;

Pupae of the Spring Brood . . . . . . . . . . . . . . . . . . . . . . . ..

Emergence of Spring-Brood Moths . . . . . . . . . . . . . . . ..

Oviposition by Moths of the Spring Brood . . . . . . . . ..

Length of Life of the Adults of the Spring Brood. . . ..
First Generation-
Incubation of the Eggs of the First Generation . . . . . ..
Larval Period of the First Generation . . . . . . . . . . . . ..
Pupae of the First Generation . . . . . . . . . . . . . . . . . . . ..
Emergence of First-Generation Moths . . . . . . . . . . . . ..
Oviposition by the Moths of the First Generation. . . . .
Length of Life of the Adults of the First Generation. . .
Second Generation— y
Incubation of the Eggs of the Second Generation . . . . . . .
Larval Period of the Second Generation . . . . . . . . . . . ..
Pupal Period of the Second Generation . . . . . . . . . . . . .
Emergence of the Moths of the Second Generation. . . .
Oviposition by Moths of the Second Generation . . . . . . . .
Length of Life of the Adults of the Second Generation.
Third Generation-
Incubation of the Eggs of the Third Generation . . . . . . . .

Larval Period of the Third Generation . . . . . . . . . . . . . .

Pupae of the Third Generation . . . . . . . . . . . . . . . . . . . . . .

Emergence of the Moths of the Third Generation . . . . . . ..

Oviposition by the Moths of the Third Generation . . . . . . .

Length of Life of the Adults of the-Third Generation. .
. Fourth Generation—

Incubation of the Eggs of the Fourth Generation . . . . . ..

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ; . . . . . . . . . . . .

 

BULLETIN N0. 347 APRIL, 1927

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE
BEARER

(A crobasis caryaie, Grate)
S. W. BILSING

There is some confusion as to the scientific name of the pecan nut
case bearer, due to the fact that there are several species of the genus
Acrobasis which have nut feeding habits. Gill, of the U. S. Depart-
ment of Agriculture in 1925 (6) published an account of the pecan
nut case bearer (Acrobasis hebescella), stating that “in 1902 E. P.
Stiles gave an account of injury in West central Texas caused by what
he called the pecan husk worm but doubtless due to Acrobasis hebescella
and a closely related species A. caryivorella, Rag.” The same author
referred to A. caryitvorella in a former publication of the U. S. De-
partment of Agriculture (4). Hulst (8) in 1890 first described Acro-
basis hebescella, and Ragonot (11) in 1890 described Acrobasis can-yi-
eorella. Grote (7) described A. caryae in 1881 from material collected
by Coquillet in Illinois. . An examination of the literature indicates that
more study needs to be given to the anatomical characters of all of
these species to separate them correctly. p

The scientific name A. caryae Grote, is here given because according
to the information at hand, the pecan nut case bearer seems to con-
form more nearly t0 A. caryare thanto either A. hebescella. or A.
caryivorella. Though Dr. Harrison Dyar has identified specimens
which have been sent him as A. caryivorella, hIcDunnough, in 1913 (9)
examined Ragonofs type specimens in the National Museum at Paris
and studied Grote’s type in the British Museum at London, concluding
from these studies that the~“true caryae” is the species Dyar identified
as "caryivoirella?

6 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Fig. 1. Adultlmoths, male and female.

   

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 7

DESCRIPTION OF THE INSECT
Adult

Size! Small. Wing expanse 20 to 22 mm. Length to tip of
abdomen 7 to 9 mm. Width of thorax 2 mm. Width at extremity of
wings when moth is at rest 5 to 6 mm. Ground color pale gray.

- Maeulation mainly defined by black scales which shade the primaries.

Head: Biackish-gray Proboscis yellow: Eyes black and very
shiny 0n livi.ng specimens when examined in the dark. Labial palps
long, grayish-black. Antennae gray, pectinate in male.

F0" Willgsi Most distinctive character is the scale ridge which
extends across the Wings transversely, one-third of the distance from
the head t0 tip of wings, the scales being blackish and feathery in ap-
pearance and always pronounced in well preserved specimens. Fore
Wings about three times as long as Wide and widest at the outer margin.
Under side of fore wing of male with a small black dash at base of
costa and a blackish subcostal streak from base to beyond middle.
Region posterior to the scale ridge may be purplish or black. A dorsal
elevation extends longitudinally from about the middle of the scale
ridge almost or quite to the extremity of the wing near the inner side
of the outer margin, making a decided bend about half way from the
scale ridge to the outer margin. There are two obliquely transverse
lines extending from the costal border, near its distal extremity, for-
ward and inward. The anterior is indistinct and in many specimens
is entirely lacking. It can seldom be determined beyond the dorsal
elevation Which it reaches at the anterior part of the bend. The
second line begins near the first on the costal border and extends to
the inner margin, near which it is deeply notched. The discal mark
usually shows as two black points but is obscured by the ground color
and sometimes is entirely lacking. The area between the second trans-
verse line and the outer margin is darker than the median part of the
wing. The outer margin is fringed and has a dark line at the base
of the fringe.

Back Wings! Uniforml_y' grayish With a dark lineat the base of
the fringe as in the fore Wings, and without secondary sexual macu-
lation.

Thflrflx! Front coxae black. Entire front legs dark or nearly
black. Second pair of legs with two tibial spurs, the outer about three
times as long as the inner. Distal end of tibia ash gray. Tarsi five
jointed, nearly’ black on outer surface and ashy on inner surface.
Distal end of tarsal joints with a fringe of yellow scales. Tibia of
third leg with four spurs in two pairs, one pair being at the distal
extremity of the tibia and the other one-third the distance from the

8 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Fig. 2. Ventral view of male genitalia.

Explanation of Figure 2.

A-Ventral view of male genitalia. a _ ‘
B—Ventral vlevsznof male genitalia (same view as A with anellus, aedoeagus, and transtllla
t‘ remove . ‘ .

C-An, Anellus (chitinous support of aedoeagus).

D——Ae,- Aedoea s (outer chitinous sheath of penis).

E——Ts, Transtil a (apostal bridge connecting the harpes).

F—Gn. Gnathos (paired organ ventral to the anus).

Hp—Harpes (clasping or ans).

U—Uncus (armature of t e- anus).

  

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STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER

Fig. 3. Female genitalia.
Explanation of Fig. 3.

Bc—Bursa copulatrix. Ds—Du_ctus seminalis.
Db——Ductus bursae. G-Genltal plate.
Sp-Spermatheca.

l
s

1O BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

distal extremity. The scales 0n the thorax are long and feathery,
those on the prothorax darker than those on the mesothorax. Half-
way from the head t0 the scale ridge the scales are almost black, the
intervening space being bluish-gray.

Abdflmell! The abdomen of the male is more slender and of a

more uniform blackish-gray color than that of the female. The base
of each abdominal segment of the female is darker than the remainder
of the segment, Which gives i.t an annulated appearance. The vaginal
opening is surrounded by a ring of yellowish hairs.

C .

Fig. 4. Eggs of the pecan nut case bearer, showing their position on the nuts.
A-—Positi0n of egg when deposited below calyx.
B——C——A single egg much enlarged.
D—-Position of egg both below calyx and at base of nut.

 

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 11

Genitalia (Wale)! The harpes or clasping organs are paddle-
shaped and are large enough to be easily seen on the male when alive.
The aedocagus or tube which contains and protects the penis is elon-
gate and is nearly as long as the entire genitalia. The anellus has
two projecting lobes. The transtilla or bridge which connects the

harpes is well developed. The gnathos has three hooks arising a short‘

distance from the distal end; proximal to the median hook is a sack-
like part (G) which fits down over it like a flap.

Genitalia (F 6111816)! The bursa copulatrix is large and balloon-
shaped. The spermatheca is nearly spherical and is connected with
the bursa copulatrix by a tube, the ductus seminalis.

Egg

The eggs are elliptical in shape and are finely reticulated. They are
just large enough (.65 mm. longx .36 mm. wide) to be seen without
the aid of a lens. When first laid they a-re bluish-white, but in a few
hours small red spots appear which later increase in size and the egg
is pinkish to reddish in color up to the time of hatching. The eggs,
convex above and flattened below, are firmly fastened to the nut by
means of a sticky substance. Upon hatching, the larva. cuts its way
out of the end of the egg, after which the shell has a snowy white
appearance. After hatching, the egg shell may be seen for several days
and sometimes for weeks if the eggs have been deposited in grooves
on the sides of the huts.

Larva

The larva when full grown is 11 to 13 mm. in length, occasional
specimens measuring 15 mm. It is cylindrical and tapers slightly near
the posterior end. When first hatched the larva is white or pinkish-
white, later turning to an olive-gray and just before pupating
changing to a jade green color. The head, mouth-parts and thoracic
and anal shields are yellowish-brown. The surface of the body is much
wrinkled and sparsely covered with white hairs. There are four pairs of
abdominal prolegs and one pair of anal prolegs.

Head nearly quadrate, broader than long when viewed from above.
Yellowish-laroivn, epicranium rugose. Margin rounded,--not deeply in-
cised at rear. Greatest width at middle. Incision of dorsal hind
margin not more than one-fourth the longitudinal distance across the
head. Front nearly triangular, not reaching the hind margin. Adfron-
tal sutures sinuate, extending less than half way from adfrontal ridge

to hind margin. Longitudinal ridge long, nearly- half the length of

head. Ocelli six; numbers 3 and 4 closer together than 3 is to 2 or
‘l: is to 5; numbers 4, 5, and 6 form a triangle. Qistance between
trontal seta F, and adfrontal seta rldfl less than the distance between

adfrontal seta Adf, and Adfgo Adfrontal seta Adi, small. Epistomal"
setae E1 and E2 well developed. Anterior setae Al, A2, and A3 form

12

BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

 

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_Fig. 5. Mapfof theIarrangement of the setae of the larvae.

   

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13

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER

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14 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Fig. 7. Drawing of the pupa.

Explanation of Figure 7.
A-Ventral view of pupa. _
B—Dorsal view of pupa.

mx =Maxilla.

11 =First thoracic leg.

12 =Second thoracic leg.

f1 =Femora of prothoracic leg.
a =Antennae. -
w =Wing. _

go =Genital openlng.

cr =Cremaster.

st =Stylets.

v =Vertex. _

t1, t2, ta =First, second and thirgi thorac1c segments.

a1 to a1o =F1rst to tenth abdommal segments.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 15

an obtuse angle. Seta A3 is closer to A1 than to A3. Posterior setae
P, and P3, a little nearer to the lon.gitudinal ridge than the margin.
Seta P, is slightly posterior to Adfl. Lateral seta L1 is closer to
A3 than A3 is to A3. Ocellar seta O1 is between and below ocelli 2
and 3 and about equidistant from them. Seta O3 large and about
the same distance from ocellus 1 as A3. Seta O3 is below O3; A3 and
O3 are situated in nearly a straight line. Subocellar seta S03 between
and below ocell.i 5 and 6; subocellar seta SO3 below and posterior to
subocellar seta S03. ~

Thoracic feet normal. Four pairs of abdominal prolegs with bi-
ordinal crochets arranged in a circle. Anal prolegs with a transverse
line of biordinal crochets. Arrangement of body setae as shown in
Fig. 5.

Labrum with median incision rounded, rather deep. Median setae
small, M, and M3 close to the margin. Mandibles longer than broad,
three teeth, sharply pointed. Antennae two jointed; first joint longer.

Before pupating, the larva spins a flimsy cocoon composed of silk
and excrement, from which is derived the name “Pecan Nut Case
Bearer.” -

Pupa

The pupa (Fig. '7) is similar to that of many other small moths.
It is 8 to 10 mm. in length. When it is first formed it is jade green
in color but a few hours after pupation it turns to a brownish-yellow
and later to a blackish-brown color. The two most distinctive char-
acters are four setae, resembling golf clubs, and the cremasters or
hooks,-—both located at the posterior end, the latter at right angles to
the longitudinal axis. i

ORIGINAL DESCRIPTION

The following is the original description given by A. R. Grote, and
is taken from Papil.io, Vol. 1, No. 2, pp. 13-14, February 19, 1881:

“Acrobasis ca-ryae. The maxillary palpi untufted, the antennae
ciliate, with a sub-basal fiexure and a scale-tooth on the thickly scaled

i basal joint. Shining grayish fuscous ; the head and thorax concolorous.

Smaller than Angusella, without the carneous shadings and reddish
thorax and head. Outer line of primaries pale, narrow and faint.
Inner line a ridge of raised darker; scales narrowly edged outwardly
by a pale, flesh-colored shade. The wing is paler, more grayish, at
base. The color shifts with the light. Discal points faint. In orna-
mentation this species is inconspicuous. Hind wings as usual blackish;
fringes interlined, concolorous. Length of primary wing, 9 mil.
Eeared by Mr. Ooquillett from larvae on Cary/a porcina; the larva has
been found “boring into the twigs.” Mr. Coquillett describes the larva
and chrysalis as follows:

“ ‘Body subcylindrical, smooth, pale greenish ‘ash; a pale brown sub-
dorsal dot on each side of segment 2; a wavy-fold below the spiracles;

16 BULLETIN NO. 3-17, TEXAS AGRICULTURAL EXPERIMENT STATION

the latter are encircled with a dark brown ring, and there is a brown
piliferous dot above each ;' a few whitish hairs on each side of the
body; top of segment 1 polished, yellowish-green; head narrower than
segment 1, heart shaped, dark brown; venter pale green, unmarked;

16 legs; length, 14L mm. Found May 21, burrowing in the branches a

of the Pignut Hickory (Caryn porcine) usually selecting the lower
branches; imagoes about June 22. ChrysaZis——Of the usual form, pale
brown, rounded at the posterior end, at which place there is a cluster
of about four slender hooked spines; length, from 7-8 mm. The
larva spins a thin web around the footstalks of the leaves which grow
near the terminal end of the branch, and then burrows into the ter-
minal bud and the wood of the present year’s growth. It Webs its
castings together and forms a short tube which projects outward from

the mouth of its burrow, and is closed at the outer end. The larva '

probably assumes the chrysalis form in its burrow, but those which I
reared deserted their burrows and spun tough cocoons beneath the
litter in the bottom of the breeding-cage. These larvae are very sub-
ject to the attacks of parasites; from a small number which I collected
I obtained three moths and two Hymenopterous parasites which Mr.
E. T. Cresson determined to be the Phanerotmna tibialis of I-Ialdeman.
One of these parasites issued June 21, and the other June 26.’ ”

LIFE HISTORY STUDIES

The study of the life history of the pecan nut case bearer was car-
ried on from 1918 to 1923, inclusive. Observations were continued in
1924 and 1925, but no detailed records were made for those years.

Pupation and emergence records, and length of life studies were
obtained for all generations and for the entire period, The tables on
egg deposition and the summaries on the oviposition records are tab-
ulated from the records obtained from cage work. The conditions
were made as nearly as possible like those of the moths under natural
conditions.

As the egg deposition records were obtained on the trees in the
orchard, the eggs remaining on the nuts where they were deposited,
the incubation period may be considered as approximating that under
natural conditions. In addition to the incubation records obtained
from reared moths, records were also obtained from free flying moths.
This was done by labelling certain limbs and careful daily inspection
of the nuts on those limbs. When eggs were deposited, the position
of the egg and the date of oviposition were recorded and a tag with
the record was attached to the nut cluster ‘containing the egg. In
this Way a check was obtained 011 the eggs obtained from reared moths.
In 1923, the larvae were reared entirely on the trees, other larvae
being prevented from gaining access to the nut clusters by means of
a piece of muslin cloth tied below the cluster and a ring of tanglefoot
applied to this. The larvae were confined to the cluster in a press-

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 17

board cylinder which Was closed at one end With a cork stopper and
at the other with a piece of cotton wrapped in tissue paper.

All the pupal and emergence records given for Olarksville, Oorsicana,
and Winona were obtained from nearly grown larvae and pupae which
were collected at those places in connection With experiments on con-

ytrol and brought to College Station, where the life history Was carried

through.

Temperature Records

All the temperature records given are those taken by the Division

of Entomology of the Experiment Station in co-operation with the
U. S. Weather Bureau. The hygrothermograph of the Division of
Entomology is located about 1100 feet from the laboratory where part
of the life history work was carried on.

The average mean temperatures were obtained by adding together
the daily mean temperatures of the period under observation and then
dividing the sum by the length of the pupal, egg or larval period.

Temperature has a very decided influence on the life history. It is
thought from this study that the minimum temperature exerts the
greater influence on the developing stages, especially in retarding
emergence and in lengthening the pupal period. Humidity also has
some influence but its exact relationship with the life history has not

been determined.
Spring Brood

The spring brood consists of the larvae which have passed the Winter,
the pupae resulting from these larvae, and the resulting moths. The
size of this brood during the period of observations was variable.
After a year when a small or moderate crop of pecans matured, the
spring brood was small. In 1.923 it was difficult to find many spring
brood larvae, except on trees which set nuts the previous year. After
a. year when there was a heavy crop of nuts the spring brood was usually
large. In 1919 a heavy crop of nuts was harvested and the spring
brood of 1920 was so large that most of the nuts which were set in
the spring of 1920 Were destroyed. '

The length of the pupal period is more variable in the spring brood
than in the three succeeding generations because low temperatures have
the efiect of lengthening the pupal period.

Larvae of the Spring Brood

The overwintering larvae consist of the non-transforming larvae of
the third generation and all of the larvae of the fourth generation,
when four generations occur.

At the approach of winter, or when there is a scarcity of food, the
larvae spin tough silken cocoons, saucer shaped andfrom one to three
millimeters in diameter, which are attached to the sides of buds, usually
between the buds and the branches. They are about the same color as
the bud itself and are much smaller than the cocoons which the larvae

18 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

spin to protect the pupae. The overwintering hibernacula are tough
and difficult to open.

When the first warm days of spring arrive, the larva begins activity
within this hibernaculum. It first feeds by cutting an opening at the

point Where it is attached to the bud. A small opening is also cut"

through the hibernaculum to the exterior, through which the larva
pushes excrement and frass.

After the bud to which the hibernaculum Was attached has been con-
sumed the larva attacks other buds and soon enters the new growth at
the axils of the leaves and main branches and then hollows out the
interior. Some larvae feed on tender leaflets a11d occasionally some are
found in the catkins. The time at which the larvae desert the over-
wintering cocoons or hibernacula, to feed on the new growth, varies
with the season and the latitude. If the weather is Warm they begin
to come from their winter quarters about the middle of March and
all of them have usually emerged by the middle of April. The point
at which a larva enters a branch may be easily detected by the excre-
ment which it pushes out. When the larva is full grown it stops up
the opening through which it entered the branch and spins a flimsy
cocoon made of silk and excrement. Then it pupates within this
cocoon.

Pupae of the Spring Brood

The time at which the overwintering larvae begin to pupate depends
to a great extent on temperature. Sudden changes in temperature and
continued windy cool weather retard pupation. Humidity has some
effect, the exact extent of which has not been determined. There is a
correlation between the activity bf the larvae and the condition of the
buds, which in turn is dependent on soil temperatures. Under normal
climatic conditions pupation begins about the 15th of April. In 1918
and 1921,'because of high mean temperatures, some larvae began to
feed during the middle of March and pupation began about April 1.
In 1921 for a period of 10 days during the middle of March, the daily
minimum temperature ranged from 65° F. to 70° F. Two pupal
records were obtained on the 27th. of March, but on the 28th. the mini-
mum temperature dropped to 37° F., and although it rose to 65° F.
on April 5th., it again dropped to 41° F. on April 11th. and remained
below 65° F. until April 24. On the 25th. of April the minimum tem-
perature rose to 74° F. and on that day maximum pupation occurred.
There were only six days from March 21 to April 25 in 1921 when
the daily minimum temperature was above 65° F.; there was not a
clear day during the month of April, and most of the days were windy.
Fluctuations in temperature and low temperatures in April in both
these years had the effect of greatly lengthening the period over which
larvae were pupating and the duration of the pupal stage. In 1921
pupation extended over a period of 41 days and the period over which
the larger number of individuals p-upated was not as well defined as

n. ._.\..... ~

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 19

in other years. The pupation curve for 1921 indicates that if the
temperature is low, pupation will finally occur even if there is no
decided rise in the temperature. The time of emergence of the adults
will be delayed for a few days—sometimes as much as a Week when
the mean temperatures are low. From a comparison of the mean tem-
peratures of 1918 and 1921 with those of 1919, 1920, 1922, and 1923, it
will be seen that a difference of from 4° F. to 6° F. in the average mean
temperatures resulted in delaying 6 to '7 days, the period over which
pupation occurred and the period over which the larger number of
larvae pupated. The average duration of the pupal period for 1918
was 17.5 days; that of 1921 was 18.5 days. The average duration of
the pupal period for 1920, when the average mean temperature was
734° F., or 7° higher than in 1918, was but 12.1 days. In 1920 and
1922 when the average mean temperatures for the duration of pupal
periods were 734° F. and 74.7” F., respectively, a large number of
larvae were pupating daily during the entire time that pupation was
taking place; and the period during which pupation occurred began
on April 16 and continued until about May 8 or about 23 days. Maxi-
mum pupation took place on April 24 in 1920 and on April 25 in 1922.

In 1919 the temperatures fluctuated more than in 1920 or 1922.
An examination of Fig. 8 shows that there were two peaks in the curve
of pupation. The minimum daily temperature remained below 60° F.
until April 5. From April 6 to April 8, the minimum daily tem-
perature was 66° F., dropping to 44° F. on April 10. As soon as it
began to rise again there was a daily increase in the number of larvae
which pupated until the maximum number was reached.

In the spring of 1923 the spring-brood larvae were scarce. Though
one person spent a month of his time collecting larvae, the number
collected from day to day was so small that a continuous record could
be obtained for only 123 individuals. Nearly half the larvae were
collected from a. single tree near the Navasota River. The reason for
the paucity of spring-brood larvae in 1923 is not known, but it is
believed that a lack of food and parasitism during the previous year
may have been the controlling factors.

In 1922 a record was kept of the native trees which set a crop of
nuts. In the spring of 1923 these were the only trees on which larvae
could be found. On this account it is believed that the lack of a
supply of nuts the previous year was in a great measure the cause of
the scarcity of spring-brood larvae in 1923. But in 1922 it was also
observed that there was a limited number of moths of the first gen-
eration, although there was a large number of first generation larvae.
Hence parasitism may have also been an important factor in reducing
the number of larvae.

20

BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 1.—Date of pupation and period over which pupation occurred. Spring brood, 1918-1923.

Number of Individuals Pupating

Year

Date of

Pqpa- 1918 1919 1920 1921 1922 1923 Total

tron
Clarks-
College College College College ville College Winona College

Mar. 27 . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Mar. 29 . . . . . . . . . . . . . . . . . . . . . . . . 1 ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

April 1 3 . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

April 2 1 . . . . . . . . . . . . . . . . 3 . . . . . . . . - . . . . . . . . . . . . . . . . . . . . . . . . 4

April 3 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

April 4 3 . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

April 5 2 . . . . . . . . . . . . . . . . 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

April 6 1 . . . . . . . . . . . . . . . . 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

April 7 2 . . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . 4

April 8 8 - . . . . . . . . . . . . . . . . 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

April 9 . . . . . . . . . . . . . . . . . . . . . . . . 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

April 10 2 . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

April 11 3 . . . . . . . . . . . . . . . . 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

April 12 6 1 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

April 13 3 6 . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

April 14 2 7 . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

April 15 9 28 . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

April 16 20 17 6 1 . . . . . . . . 1 . . . . . . . . . . . . . . . . 45

April 17 21 6 18 5 . . . . . . . . 16 . . . . . . . . . . . . . . . . 66

April 18 15 7 17 7 1 16 . . . . . . . . . . . . . . . . 63

April 19 12 4 15 5 2 15 . . . . . . . . . . . . . . .. 53

April 20 2 9 16 13 4 34 3 . . . . . . . . 81

April 21 . . . . . . . . 20 15 6 5 13 3 . . . . . . . . 62

April 22 3 44 21 3 9 16 3 . . . . . . . . 99

April 23 7 32 21 5 1 20 7 . . . . . . . . 93

April 24 2 29 64 13 10 64 6 . . . . . . . . 188

April 25 . . . . . . . . 10 49 46 17 112 30 . . . . . . . . 264

April 26 1 4 32 8 23 28 49 . . . . . . . . 145
April 27 3 6 4 6- 10 31 45 3 108
April 28 . . . . . . . . . . . . . . . . 11 25 16 34 24 35 145

April 29 . . . . . . . . . . . . . . . . 11 1 4 12 5 18 51

April 3O . . . . . . . . . . . . . . . . 14 8 . . . . . . . . 14 6 5 47

May 1 . . . . . . . . 3 20 1 7 24 6 7 68

May 2 . . . . . . . . 1 22 2 10 30 . . . . . . . . 4 69

May 3 . . . . . . . . 1 26 2 2 51 11 2 95

May 4 . _ . . . . . . . . . . . . . . 2 1 3 35 11 6 58

May 5 . . . . . . . . . . . . . . . . 12 1 1 11 13 2 40

May 6 . . . . . . . . . . . . . . . . 4 . . . . . . . . 4 45 . . . . . . . . 3 56

May 7 . . . . . . . . . . . . . . . . 2 . . . . . . . . 2 12 4 9 29

May 8 . . . . . . . . . . . . . ~ . . 2 . . . . . . . . 1 8 4 3 18

May 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 . . . . . . . . 1 17

May 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6

Mayll . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4 . . . . . . .. 3 7

May 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . 7 8

May 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2

May 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 1 3 5

.May 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2

May 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . . . . . . 2 2
Total _ 132 235 405 228 133 663 231 123 2150

21

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER

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22 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 3.—Summary of the length of the pupal period of the pecan nut case bearer. Spring
brood, 1918-23.

Date of Period Number Length of Pupal
0v_er indlvid- Stage, Days
Year Place which uals ——
First Maximum Last pupation observed
Pupation Pupation Pupation occurred Avg. Max. Min.
1918 College... April 1.... April 17... April 27. .. 27 132 17.5 24 9
1919 College... April 12... April 22... May 3.... 22 235— 13.6 18 11
1920 College... April 12... April 24. .. May 8. . .. 27 405 12.1 16 8
1921 College... Mar. 27. . . April 25. .. May 6.... 41 228 18.5 24 14
' Clarks-

ville... April 18... April 26... May 12. . . 25 133 17.3 20 14
1922 College... April 16... April 25... May 14. . . 29 663 13 .8 21 9
Winona. . April_20.. . April 26... May 14. . . 25 231 14.9 19 11
1923 College... April 27. .. April 28... May 16. . . 20 123 14.4 18 10
Total. . . . . . . ..g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2150 . . . . . . . . . . . . . . . . ..

Because of the relatively small number of larvae collected and the
fact that the greater number were collected from one tree, it is scarcely
possible to arrive at any conclusions with regard to the effect of tem-
perature on the time of pupation. It will be seen, however, that the
minimum temperature was above 60° F. most of the time from April
5 to April 14, and on April 14 dropped below 60° F., reaching 48° F.
0n April 17. On April 21 the minimum temperature began to rise and
reached 72° F. on April 24 and 25 and maximum pupation occurred
on April 28. -

The period during which pupation occurred was considerably de-
layed in 1923, although maximum pupation took place but four days
after the time of maximum pupation in 1922 and five days after
maximum pupation occurred in 1920. When the mean temperature
remains below 60° F. during the month of March, the larvae do not
begin feeding until early in April. In such a case pupation normally
begins about the 15th. of April. In years when the daily minimum
temperature did not often fall below 65° F. or did not remain below
65° F. for any length of time after the larvae began to feed, pupation
began about the 15th. of April and was completed in about 27 days,
and a considerable number of larvae pupatedeach day over the period
when pupation was taking place. But in years when the mean tem-
perature was high enough to start tree growth before March 20th.,
the larvae came from their hibernacula and began feeding. If this
period was followed by low temperatures for any considerable length
of time the period during which pupation occurred was lengthened
from 5 to 14 days and the average duration of the pupal stage was
lengthened from 4 to 6 days. -

Great fluctuations in‘ either the mean temperature or the daily mini-
mum temperature had the same effect as low temperature.

STUDIES ON THE BIQL£G£IIQ§T'FE'GRN%NQT?QA§E EEARER
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Fig. 8. Pupal records and temperatures for the spring brood. College Staiion, 1918-1923

24 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

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STUDIES ON THE BIOLOGY OE THE PECAN NUT CASE BEARER 25

Emergence of Spring-Brood Moths

The moths emerge at night. The males begin emerging first and it
is possible to determine the progress of the generation by the prepon-
derance of males or females.

When the adult is fully formed the pupal case splits open at the
larger end and the moth emerges.

The time of emergence and the length of the period over which the
adults emerged is dependent on the temperature during the time the
insect is in the pupal stage. If the mean temperatures are 10W, emer-
gence is continued over a long period of time. In 1918 and 1921 the
moths emerged over a period of 29 and 36 days, respectively, but in 1920
and 1922 when the mean temperatures Were a few degrees higher
emergence Was completed in 26 days and 22 days, respectively. A large
number of moths emerged daily over the greater part of the time dur-
ing which emergence Was taking place in 1920 and 1922, while in 1918
and 1921 emergence occupied a longer period.

The moths of the spring brood began to emerge as early as April 15,
but emergence in large numbers occurred only from April 28 to May 6.
Except in the years 1918 and 1921, when the average mean temper-
ature of the pupal period Was about 65° F, emergence was completed
in from 22 to 26 days. It is a significant fact as regards control that
the time of maximum emergence varied but 8 days in the six years,
occurring on May 5 in 1919; on May '7 in 1918 and 1920; on May 9
in 1922; and on Hay 13 in each of the years 1921 and 1923.

Table 5. Summary of the emergence records of the spring-brood moths of the pecan
nut case bearer. 1918-1 23.

Number
Date of Days on Number
Year Place which moths Number Number
- _ Emergence Ob- Males Females
First ' Maximum Last Occurred served
Emergence Emergence Emergence
1918 College... . April 16. . . May 7. . .. May 14... 29 106 56 50
1919 College... . April 27... May 5.... May 17... 21 187 84 103
1920 College. .. April 26... May 7... . May 21... 26 380 178 202
1921 College... . April 15.. . May 13... May 20... 36 202 116 86
College,
Corsicana,
Clarllfs- April 15. . . May 13.. . May 23.. . 39 333 165 168
v1 e.
1922 College... . May 3.... May 9.... May 24... 22 639 298 341
College,
Winona. . . May 3.... May 10... May 24... 22 820 395 425
1923 College... . May 7.... May 13... May 28... 22 196 71 125
Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .‘ . . . . . . 2022 949 1073

_ 4.1 A.,.—-~<——<—A- —

26

‘ig. 9.

. BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Emewrx: B321"

         
 

 

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Emergence records and temperatures for the spring brood. College Station, 1918-1923 .

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 27

Oviposition by the Moths of the Spring Brood

The records on egg deposition were difiicult to obtain, and since the
moths do not behave normally in captivity, it is very probable, though
field conditions were reproduced as nearly as possible, that these rec-
ords are not representative of what occurs in the field. All the records
were obtained in breeding cages on the trees. It is probable that the
maximum number of eggs obtained in the cages would be nearly the
average number deposited by any single moth under field conditions.

The eggs in this brood are usually placed in the tips of the nuts.
Eggs may be deposited on the upper or lower surface of the calyx and
occasionally one is deposited in the grooves at the tips and bases of
the nuts. Most of them are so placed that they are difficult to find.
A moth seldom deposits more than one egg in a cluster of nuts. The
majority of the moths died without ovipositing. '

In the cage, experiments in 1922 the first eggs deposited were laid
on May 8. Observations made on nuts under field conditions showed
that eggs had been deposited a few days prior to that time. Ovi-
position records were obtained from 64 moths. This was but a small
per cent of those caged, as most of them died in the cages without
ovipositing. Most of the surviving moths in the cages laid a small
number of eggs. From dissections made it is thought that the maxi-
mum number laid in cages is nearly the average number under field
conditions. The last eggs in the cages were obtained on May 26. The
maximum number of eggs laid by one individual was 163, and this one
escaped before the oviposition record was completed. The average
length of life of the females that oviposited was 7.1 days. The aver-
age time from emergence to the first oviposition was 4.1 days. Ovi-
position occurred over an average of 1.4 days and the average time
from emergence to last oviposition was 5 days. The average time from
the last oviposition until the moth died was 2.1 days.

In 1923 the first eggs deposited by caged moths were laid on May 15.
As it was not possible to get eggs from moths in cages until a. con-
siderable number had emerged, the first date of egg deposition in
cages was a few days after that observed under field conditions.

Oviposition records were obtained from 36 females. The maxi--
mum number of eggs laid by one female was 142, deposited over a
period of four nights.

The average life of the females which oviposited was 8.5 days; the-
average time from emergence to first oviposition was 3 days, and the
average time over which oviposition occurred was 2.7 days. An aver-
age of 6.5 days elapsed from emergence to last oviposition and the
average life after the last oviposition was 2 days.

28

BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 6.-—Summary of the oviposition records of the spring-brood moths of the pecan

nut case bearer.

College Station Texas, 1922.

E h” w H» . m m ‘H - o .
- ..- 0"“ >500: 00w g -
8 a a a5 ~a=€ Q55. 553,9 5:8
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1 . . . . . . . . . . . .. May 3 May 8 5 1 5 1 5 O

2 . . . . . . . . . . . .. May 5 May 8 3 3 3 l 3 0

3 . . . . . . . . . . . .. May 5 May 10 5 31 3 2 4 1

4 . . . . . . . . . . . .. May t6 May 10 4 35 3 l 3 1

5 . . . . . . . . . . . .. May 6 May 15 9 8 3 1 3 6

6 . . . . . . . . . . . .. May 6 May 9 3 5 3 1 3 0

7 . . . . . . . . . . . .. May 6 May 10 4 8 3 l 3 1

8 . . . . . . . . . . . .. May 6 May l0 4 3 3 1 3 1

9 . . . . . . . . . . . .. May 7 May 15 8 5 5 2 8 0

10 . . . . . . . . . . . .. May 9 May 14 5 14 2 4 5 0

11 . . . . . . . . . . . . . May 9 May 22 13 8 3 4 7 6

12 . . . . . . . . . . . .. May 9 May 13* . . . . . . .. 163 3 . . . . . . . . . . . . . _ . . . . . . . . . .

13 . . . . . . . . . . . .. "May 9 May 16 7 10 3 2 4 3

14 . . . . . . . . . . . .. May 9 May 13 4 15 3 1 3 1

15 . . . . . . . . . . . .. May 9 May 13 4 58 3 2 4 O

16 . . . . . . . . . . . . . May 9 May 22 13 5 4 1 4 9

17 . . . . . . . . . . . .. May 9 May 17 8 15 3 4 8 0

18 . . . . . . v . . . . . . May 9 May 26 17 1 6 1 6 11

19 . . . . . . . . . . . .. May 9 May 13 4 3 3 1 3 1

20 . . . . . . . . . . . .. May 9 May 13 4 1 4 l 4 0

21 . . . . . . . . . . . .. May 9 May 13 4 3 3 1 3 1

22 . . . . . . . . . . . .. May 9 May 14 5 1 3 1 3 2

23 . . . . . . . . . . . .. Ma 9 May 18 9 29 3 3 9 0

24 . . . . . . . . . . . .. Ma 9 May 17 8 21 4 1 4 4

25 . . . . . . . . . . . .. May 9 May 15 6 80 4 2 5 1

26 . . . . . . . . . . . . . May 9 May 22 13 4 4 2 9 4

27 . . . . . . . . . . . .. May 9 May 13* . . . . . . .. 114 3 . . . . . . . . . . . . . . . . . . . . . . . .

28 . . . . . . . . . . . .. May 9 May 15 ~6 28 3 2 4 2

29 . . . . . . . . . . . .. May 9 May 14 5 7 4 2 5 0

30 . . . . . . . . . . . . . May 9 May 22 13 86 4 1 4 9

31 . . . . . . . . . . . _ . May 9 May 20* . . . . . . . . 65 4 . . . . . . . . . . . . . . . . . . . . . . . .

32 . . . . . . . . . . . .. May 11 May 3 2 1 2 1 2 0

33 . . . . . . . . . . . .. May 11 May 14 3 4 2 1 2 1

34 . . . . . . . . . . . .. May 11 May 18 7 1O 3 1 3 4

35 . . . . . . . . . . . .. May 11 May 14 3 1 3 1 3 O

36 . . . . . . . . . . . .. May 11 May 16 5 3 3 1 3 2

37 . . . . . . . . . . . .. May 11 May 16 5 7 4 1 4 1

38 . . . . . . . . . . . .. May 11 May 17 6 6 6 1 6 O

39 . . . . . . . . . . . .. May 11 May 18 7 2 5 1 5 2

40 . . . . . . . . . . . . . May 11 May 23 12 9 3 4 11 1

41 . . . . . . . . . . . .. May 11 May 22 l1 2 4 2 7 4

42 . . . . . . . . . . . .. May ll May 16 5 1 3 1 3 2

43 . . . . . . . . . . . .. May 11 May 17 6 2 4 1 4 2

44 . . . . . . . . . . . .. May 11 May 17 6 1 4 1 4 2

45 . . . . . . . . . . . . . May 12 May 22 10 5 3 2 4 6

46 . . . . . . . . . . . . . May 12 May 22 10 23 5 2 8 2

47 . . . . . . . . . . . .. May 13 May 22 9 7 5 1 5 4

48 . . . . . . . . . . . .. May 13 May 18 5 2' 5 1 5 0

49 . . . . . . . . . . . .. May 13 May 18 5 1 4 1 4 1

50 . . . . . . . . . . . .. May14May17*....._... 40 4 . . . . . . . . . . . . . . . . . . . . . . ..

51 . . . . . . . . . . . .. May 14 May 22 8 25 7 l 7 1

52 . . . . . . . . . . . .. May 14 May 18 4 1 4 1 4 0

53 . . . . . . . . . . . .. May 14 May 22 8 1 4 1 4 4

54 . . . . . . . . . . . .. May 14 May 25 11 20 5 3 11 O .

55 . . . . . . . . . . . .. May 15 May 20* . . . . . . .. 38 5 . . . . . . . . . . . . . . . . . . . . . . . .

56 . . . . . . . . . . . .. May 15 May 23* . . . . . . .. 17 8 . . . . . . . . . . . . . . . . . . . . . . ..

57..- . . . . . . . . . .. May 15 May 24 9 1 9 1 9 0

58 . . . . . . . . . . . .. May 15 May 24 9 1 3 1 3 6

59 . . . . . . . . . . . .. May 16 May 24 8 4 7 1 7 1

60 . . . . . . . . . . . .. May 16 May 28 12 3 7 1 7 5

61 . . . . . . . . . . . . . May 17 ay 11 12 8 1. 8 3

62 . . . . . . . . . . . .. May 18 May 23* . . . . . . .. 10 4 . . . . . . . . . . . . . . . . . . . . . . . .

63 . . . . . . . . . . . . . May 2O May 28 8 5 6 1 6 2

64 . . . . . . . . . . . .. May 21 May 28 7 3 5 1 5 2

*Indicates moth escaped or was killed before record was completed.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 29

Table 7.—Summary of the oviposition records of the spring-brood moths of the pecan
nut case bearer. College Station, Texas, 1923.

. .2 i-P- we»: ~ w we»: - a -
3 a s gs   $25.,- ggsi 
,3 d-l d4 10-‘ It)
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EVE 3-95 m T6“ 532p EG>U E2§> mfi>
Ell  5 E0 Em 0Q EOQQ Est-t 0Q 
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May 8 May 23 15 31 7 5 13 2
May 9 May 15* . . . . . . .. 74 4 . . . . . . . . . . . . . . . . . . . . . . ..
May 11 May 20 9 59 4 5 9 0
May 12 May 26 14 27 10 3 12 2
May 12 May 17 5 6 3 1 3 2
May 13 May 22 9 7 9 1 9 0
May 13 May 20 7 16 5 2 7 0
May 13 June 2 20 43 6 - 8 19 1
May 13 May 28 15 65 7 4 1O 5
May 14 May 21* . . . . . . .. 37 3 . . . . . . . . . . . . . . . . . . . . . . ..
May 14 May 20 6 2 3 2 5 1
May 14 May 24 10 16 4 2 6 4
May 14 May 24 10 43 4 6 9 1
May 15 May 23 8 19 4 1 5 3
May 15 May 20 5 32 4 1 4 1
May 15 May 28 13 15 5 1 5 8
May 18 May 20' 2 28 2 1 2 0
May 18 May 28 10 42 4 4 8 2
May 18 May 28 10 30 2 6 9 1
May 18 May 27 9 142 2 4 5 4
May 18 May 30 12 83 2 8 1O 2
May 18 May 21 3 4 2 1 2 1
May 18 May 21 3 7 2 1 2 1
May 18 May 24 6 8 2 2 4 2
May 19 May 27* . . . . . . .. 18 4 . . . . . . . . . . . . . . . . . . . . . . ..
May 19 May 30* . . . . . . .. 15 3 . . . . . . . . . . . . . . . . . . . . . . ..
May 19 May 24 5 3 5 1 5 0
May 19 May 23 4 4 3 1 3 1
May 19 May 30 11 25 3 3 l0 1
May 19 May 28* . . . . . . .. 28 3 . . . . . . . . . . . . . . . . . . . . . . ..
May 19 May 28 9 4 3 3 6 3
May 19 May 27 8 2 4 1 4 4
May 21 May 26 5 1 3 1 3 2
May 21 May 26 5 1 3 1 3 2
May 21 May 26* . . . . . . .. 19 3 . . . . . . . . . . . . . . . . . . . . . . ..
May 21 May 28 7 4O 3 3 5 2

*lndicates moth escaped or was killed before record was completed.

Length of Life 0f the Adults of the Spring Brood

The records on the length of life Were obtained entirely from moths
in captivity. The length of life may be shortened in captivity by
several factors. One of the most difficult of these to control Was tem-
perature. If the moths are kept in the sun or if too high a tem—
perature existed in the mating cages the length of life Was much
shorter than When a lower temperature Was maintained by spraying
Water on the cages several times a day. The fact that the moths Were
confined to a limited space may also have shortened the length of life.
The females begin to oviposit a few nights after they emerge. The
fact that they deposit their eggs in from one to twelve days is an
indication that the length of life is rather short. The length of life
Was longer When more care Was taken in feeding individual moths With
a medicine (lroppcr than when they Were fed collectively With an
atomizer.

3O BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 8.——Length of life 0f the adults of the spring brood, 1918-1923.

1918 1919 1920 1921 1922 1923
Length of Life,
Days
Male Fem. Male Fem. Male Fem. Male Fem. Male Fem. Male Fem
1 . . . . . . . . . . . . . .. 3 3 4 20 26 5 11.....  

2 . . . . . . . . . . . . . .. 3 1 2 5 2O 21 3 2O 3 6 1 2

3 . . . . . . . . . . . . . .. 4 1 12 16 19 14 17 9 1O 6 2 4

4 . . . . . . . . . . . . . .. 4 6 6 12 2 7 13 11 24 25 6 5

5 . . . . . . . . . . . . . .. 4 8 13 5 9 11 12 12 19 19 2 4

6 . . . . . . . . . . . . . .. 4 5 3 .. 2 5 7 4 12 17 6 7

7 . . . . . . . . . . . . . .. 4 4 7 2 .. 3 1 6 7 2 6

8 . . . . . . . . . . . . . .. 8 3 3 3 4. 1O 12 2 3

9 . . . . . . . . . . . . . .. ... 2 3 1 .. ... 1 10 8 2 6

1O . . . . . . . . . . . . . .. 1 1 ..... .. 5 9 1 5

11 . . . . . . . . . . . . . ..  1 3 2 1 2

12 . . . . . . . . . . . . . ..  2 1 3 

13 . . . . . . . . . . . . . .. 2 2 . . . . . . . . .. 1 5 1 1

14 . . . . . . . . . . . . . .. 2 1. . . . . . . . . . . . . . .. 1  1

15 . . . . . . . . . . . . . .. ... . 1 1 .. 3

16 . . . . . . . . . . . . . .. 2.  

19 . . . . . . . . . . . . . .. 1

20 . . . . . . . . . . . . . . . . . . .. 1
Avera e length of

lie . . . . . . . . .. 6.4 6.5 5 3.81 2.52 2.65 4.20 3.21 6.22 6.47 6.15 7.64
Maximum . . . . . . .. 19 18 12 12 6 6 8 9 15 15 13 2O
Minimum . . . . . . .. 1 1 1 1 1 1 1 1 2 2 2 2

First Generation

The first generation begins with the incubation of the eggs deposited
by the spring-brood moths. The first generation consists o1": the:

(a) Eggs of the first generation.

(b) The resulting larvae, or larvae of the first generation.
(c) The pupae of the first generation.

(d) The moths of the first generation.

From the time of the deposition of the first eggs to the death of the
last moths of this generation Was 66 days in 1922. The time from
the deposition of the first eggs in 1923 to the death of the last moths
was 70 days. Hence it may be considered that it requires about 70
days to complete the first generation.

Incubation of the Eggs of the First Generation

The incubation period was determined in the field under natural
conditions. An examination of the eggs was made on the trees each
day. The nuts on which eggs were deposited were not removed from
the tree, in view of the fact that the nuts dry out very quickly once
they are removed and often dry up entirely before the eggs hatch.
When first- laid the eggs are bluish-white. A few hours after, small
red spots appear, which increase in size, giving the egg a reddish
mottled appearance. The larva cuts its way out of the end of the

. -egg and after hatching the shell is white and often adheres to the nut

‘for a long time.

.. g auuaama;;:¢¢}:lai§?ki2$$flTa<=-.»-. ‘

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STUDIES ON THE BIOLOGY OF THE PECAN NUT. CASE BEARER 31

The incubation period was obtained from 1918-1921 by selecting

certain limbs which were easily accessible from the ground, tagging
them and then making daily examinations t0 see if any eggs were
deposited by free flying moths. A large number of eggs could not be
obtained in this fashion and the records for those years are more or
less fragmentary. For this reason in 1922 and 1923 the eggrecords
were made entirely from moths confined in small breeding cages. The
results of this method were checked against the hatching period of the
eggs deposited by free flying moths, little or no difference being found
between the two.

In 1922 the minimum incubation period was 4 days, the maximum
7 days, and the average 5.6 days. A total of 860 eggs was observed.

In 1923 the minimum duration of the egg stage was <1 days, the
maximum 7 days and the average 5 days.
observed.

A total of 713 eggs was.

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32

 

‘ ixf; i

STUDIES ON THE BIOLOGY OF THEiPECAN NUT CASE BEARER 33

Larval Period 0f the First Generation

It Was difficult to obtain data on the length of the larval period and
the records of 1923 only are included in this study. The difiiculty in
securing larval records Was due to the fact that when larvae were
allowed to feed under natural conditions a large number were de-
stroyed by predaceous and parasitic enemies. Many were also lost be-
cause of the larval habit of crawling rapidly about as soon as they
hatch. If the nuts were removed to the laboratory they dried up so
quickly that the feeding of larvae was more or less irregular. The
larval records given in Table 10 were obtained by rearing the larvae
on the trees, where they were protected by cages made of press board.

On hatching from the eggs the majority of the larvae fed on buds
for a short time, usually about two days, before they entered the nuts,
although some entered the nuts a short time after hatching. The
larvae of the first generation nearly always enter the nuts by cutting
circular holes at the bases. Before cutting into the nut a silken web
is attached to the nuts and forms a protected place for the larva while

I it is feeding.

Table 10.—-Length of the larval stage. First generation. 1923.

Number of Average Mean
Length of Larval Stage—Days Records Temperature
17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 .2

18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 .3

19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 79 .2

20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 79 .1

21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 79 .2

22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 79 .5

23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 79 .6

24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 79 .8

25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 80 . 1

26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 80 .3

27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 80 .2

28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 80 .6

29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 80 .1

30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 80 .5

31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 80 .8

32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 81 .1

33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 80 .0

34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 80 .4

35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . 1 80 .6

40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 80 .3

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 80 .0

Average length of larval stage—1923, 25 .6 days.

The larva prefers to remain in dry nuts when not feeding and selects
a hard dry nut in which to pupate. One can distinguish the char-
acteristic work of this larva from that of other pecan feeding insects
by its habit of pushing the excrement out of the burrow when feeding
in the limbs and in the nuts. The larva is very active until a short
time before it pupates when it stops up the entrance hole with pellets
of excrement and silk and spins a flimsy cocoon on the inside of the
nut. When first hatched the larva is White in color, later turningto

34 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

an olive gray and just before pupation changing to a jade ‘green. 
The length of the larval 
period ranged from 1'7 days as a minimum to 4O days as the maximum.

Records were obtained on 81 individuals.

The average larval period was 25.6 days.

Pupae of the First Generation

The pupal period is passed inside the nuts and inside the cocoon
spun by the larva. Temperature which is an important factor in de-
termining the length of the pupal period in the spring brood does not
operate to the same extent in controlling the length of the pupal period
in this generation. This is probably due to the fact that both the
mean and minimum temperatures have reached a height Where tem-
perature is not as important a controlling factor and also to the fact

that there is less fluctuation in the temperature during the time in . is

which the first generation is passed.

' The duration of the pupal period ranged from 5 to 16 days, but
the average length, of thepupal period for the several years varied
but little. In 1918 When the average mean temperature Was about
83° F. for the duration of the pupal period, the average length was
8.5 days. In the succeeding five years the average duration was 9.6,
9, 9.5, 9, and 9.4 days, respectively.

There Was more variation in the time pupation occurred than in
the length of the pupal period. This variation was due in great measure
to the time that the spring-brood moths emerged and the temperatures
during the development of the larvae of this generation. In the three
years, 1918, 1919, and 1921 the first larvae pupated during the last
three days of May. In 1921 and 1922 the first larvae pupated on
June 6. In 1923 the first larva pupated on June 12th. The spring
brood was much later in 1923 than in any other year, which probably
accounts for the corresponding delay in the period over which pupation
occurred.

    

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER

Table 11.——Date of pupation and period lcgier

8 1923.

which pupation occurred.

35

First generation .

Number of Individuals Pupating

Year
Date of 1918 1919 1920 1921 1922 1923 Total
Pupation _ _
Col- Col- Col- Cors1- Col- W1n- Col- Corsi- Win- Col-
lege lege lege cana lege ona lege cana ona lege
‘Vlay 29.. . 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

May 31.. . 1 1 .4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

June 1 . . . . . . . . . 1 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

June 2. . . . . . . . 1 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

June 3.. 4 . . . . . . 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

June 4. . 7 2 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

June 5.. 5 1 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37

June 6.. 2 2 17 . . . . .. 1 . . . . .. 24 . . . . . . . . . . . . . . . .. 46

June 7.. 5 . . . . .. 30 . . . . .. 5 . . . . .. 6 . . . . . . . . . . . . . . . .. 46

June 8.. 20 . . . . .. 20 . . . . .. 2 11 . . . . . . . . . . . . . . . . . . . . . .. 53

June 8... 15 14 23 . . . . .. 5 4 1 . . . . . . . . . . . . . . . . .. 62

June 10... 22 3 17 . . . . .. 3 2 6 . . . . . . . . . . . . . . . . .. 53

June 11.. 22 6 27 . . . . .. 7 10 17 . . . . . . . . . . . . . . . . .. 89

June 12.. 25 . . . . .. 14 . . . . .. 8 9 17 . . . . . . . . . . .. 1 74

June 13. . 5 14 13 . . . . .. 5 15 23 . . . . .. 1 5 81

June 14. . 5 9 4 . . . . .. 3 15 6 . . . . .. 9 5 56

June 15.. 7 7 1 . . . . .. 5 , 8 5 . . . . .. 8 4 45

June 16.. 2 29 4 . . . . .. 6 19 10 . . . . .. 9 9 88

June 17 . . 7 18 5 . . . . .. 2 20 6 . . . . .. 8 12 78

June 18. . 4 12 . . . . .. 2 . . . . .. 11 1O . . . . .. 7 23 69

June 19. . . . . . .. 29 2 3 . . . . .. 7 2O . . . . .. 18 17 96

June 20. . . . . . . . 22 2 21 5 22 5 . . . . . . 19 11 107

June 21... . . . . .. 17 2 15 . . . . .. 10 14 9 14 13 94

June 22... . . . . .. 17 1 20 . . . . .. 18 6 12 9 9 92

June23... . . . . .. 7 . . . . .. 9 . . . . .. 15 . . . . .. 9 6 14 6O

June 24... . . . . . . . . . . . . . . . . .. 6 . . . , .. 11 8 15 12 13 65

June 25... . . . . .. 4 1 8 . . . . .. 8 4 7 35 17 84

June 26.. . . . . .. 4 . . . . .. 2 . . . . .. 10 6 7 36 15 80

June27... . . . . .. 2 . . . . .. 1 1 . . . . . . . . . . .. 8 9 12 33

June 28... . . . . . . . . . . . . . . . . .. 2 . . . . .. 2 2 4 9 15 34

June29... . . . . . . . . . . .. 1 4 . . . . .. ~1 . . . . .. 2 6 4 18

June30... . . . . .. 1 . . . . .. 2 . . . . . . . . . . . . . . . . . . . . . . .. 6 2 11

July 1... . . . . .. 4 . . . . .. 1 . . . . . . . . . . . . . . . . .. 2 10 1 18

July 2.. . . . . . . 2 . . . . . . 1 . . . . . . 2 . . . . . . . . . . . . 3 1 9

July 3.. . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . 2 2 . . . . _ , 3

July 4.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 1 4

July 5.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

July 6.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . 1

July 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  0

July 8 .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 3
Total. 161 229 249 101 58 230 196 78 240 206 1748”

36 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

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STUDIES ON THE BIOLOGY OF‘ THE PECAN NUT CASE'BEARER 37

Puloatio-n Cur Vi
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Fig. 10. Pupal records and temperatures for the first generation. College Station, 1918-1923

38 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Although temperature does not play as important a part as in the
duration of the pupal stage of the spring brood, it is still effective.
In 1918 the lowest average mean temperature for any pupal period
was 80.5° F. In 1919 the lowest was 731° F. and the highest was
81.5° F. In addition the daily maximum and minimum temperatures
fluctuated considerably. As a result the time over which pupation
occurred in 1919 extended from May 31 to July 2, a period of 33 days.
The larger number of larvae pupated between June 3 and July 1, over
the six-year‘ period, although there was considerable variation from
year to year.

The range of pupation for Corsicana cannot be considered as indica-
tive of field conditions as it was not possible to make daily collections
of larvae at that place.

Table Iii-Summary of the length of the pupal period of the pecan nut case bearer.

First generation. 1918-1923.
Period Number
Date 0f— Over Indivi- _ Length of Pupal
_ Which duals Stage-—Days
Year Place Flrst Max. Last Pupation Observed ——————-—Z—
Pupa- Pupa- Pupa- Occurred
tion tion tion Avg. Max. Min.
1918 College... ... May 29 June 12 June 18 21 161 8 .5 12
1919 College...  May 31 June 16 July 2 33 229 9.6 13 7
June 19
9 0 College . . . . .. May 31 June 5 June 29 3O 249 9.0 11 5
1 2
Corsicana. . . June 18 June 20 July 3 16 101 9.8 13 7
1921 College... .. . June 6 June 12 June 28 23 58 9.5 12 7
Winona. . .. . June 8 June 2O July 2 25 230 10.6 - 13 7
1922 College . . . . . . June 6 June 6 June 28 23 196 9 13 6
Corsicana. . . June 21 June 24 July 4 14 78 9 .8 12 8
Winona. . .. . June 13 June 26 July 8 26 240 9 .7 13 6
1923 College. .. .. . June 12 June 18 July 8 27 20_6 9 .4 16 8
Total. . . . . . . . . . . . . .» . . . . . . . . . . . . . . . . . . . . . . . . 1748

Emergence of the First-Generation Moths

The time of emergence of the moths of this generation depended on
the temperatures during the period of pupal development and also upon
the time when the moths of the spring brood oviposited.

Since the pupal period is passed within the nuts in this generation,
the moths upon emerging make their exit through the hole which the
larvae entered.

Emergence of first-generation moths began between June 5 and June
15 in the several years and was completed between June 28 and July
16. During the six years the greater number of moths emerged over
the period from June 9 to July 10 when the average mean temperature
was approximately 80° F, for the duration of the pupal period. Maxi-

 

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39

   
     
 
     
     
 
   
 

 

 

 

 
 
 

 
 
 
 
 
 

 
 
 

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER

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4O BULLETIN NO. 347, TEXAS AGRICULTURAL‘ EXPERIMENT STATION

Erner 'e.nce curve
"Ti-rs Gefléfa-‘l’

 

numbe? 0 mo b;
Z

;_.,_ .

Humbér 01? moH1$

Te m pe raTuTe 33hr:

Iunfi  Iunfl A 

Fig. 11. Emergence records and temperatuliegs] goli first generation. College Station, Texas

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 41

mum emergence took place between June 14 and June 22 in 1918,
1920, 1921, 1922 and 1923, but in 1919, when the average mean tem-
perature during the pupal period was below 80° F., maximum emergence
did not occur until June 28. »

The number of moths emerging varies considerably from year to
year, and this seems to be the most variable of the four generations.
When there Were but two annual generations there was a large num-
ber of first generation moths. In the years when there were four gen-
erations the number was also variable; in 1919 and especially in 1921
it was diflicult to collect larvae and the number of moths which emerged
was small; in 1923, however, it was comparatively easy to collect a
large number of larvae and 519 records were obtained on emergence.

Table 15.—-Summary of the emergence records of the first-generation moths of the pecan
nut case bearer. 1918-1923.

Period
Date of Over Number '
which Moths Number Number
Year Place First Maximum Last Emergence Ob- Males Females
Emergence Emergence Emergence Occurred served
1918 College... . June 5... June 14... June 28... 24 333 145 188
1919 College... . June 13. . . June 28... July 10... 28 222 103 119
College... . June 6... June 15. .. July 8. .. 33 389 219 170
1920 College and
Corsicana.. June 6... June 15... July 13... 38 _ 537 289 248
1921 College... . June 11.. . June 11.. . July 8... 28 152 56 96
College and
Winona. . . June 11.. . June 23... July 14... 34 456 209 247
College... . June 13... June 19... July 8... 25 245 106 139
June 27.. .
1922
College,
Corsicana
and June 13. . . June 30. .. July 14.. . 32 1108 478 630
Winona ~ _
1923 College... . June 15. . . June 22... July 16... 32 519 231 " 288
Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3175 1455 1720

Oviposition by the Moths of the First Generation

The moths of this generation begin to oviposit on the third or fourth
night after emergence. At this time the calyx and pistil have become
dry and hard and do not afford favorable places for egg deposition.
The eggs are deposited in grooves at the tips and bases of the nuts
and on buds immediately below the nut clusters. A nut cluster is
usually selected which has several nuts in it, especially when the eggs
are laid 011 the buds. All of the egg records were obtained from moths
in captivity. During the first years the egg records were obtained by

tagging limbs because it was not possible to obtain a continuous egg '

laying record in cages from many individuals, but this was finally
abandoned for the cage method.

42 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 16.——Summary of the oviposition records of _the first-generation moths of the pecan
nut case bearer. College ‘Statxon, Texas. 1922.

. a" J3 w s»: - w w em - .2 - ~
g a 5 35 we; 2&5 . $535 5:5
5 »» =._. E ,,, Q ELF»; Q 3,118 Q E ,1: .,_, “BE
Moth ° o ~o g mo"; "‘mg_, Om G4‘,
Number “an 2' ; 7% 7 “o “'q°“ “m'°"° ¢..°
°"= B 5 ‘m Bawa 233.95 Eawe Me-
vE q,>._. w Eh‘ Eo§> E¢>o Eog> ‘$08215
Eli-l  i 8 ‘SO  0Q EOOQ  GO 
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June 19 July 2 13 1 4 1 4 9
June 19 July 24* . . . . . . .. 11 4 . . . . . . . . . . . . . . . . . . . . . . . .
June 19 June 27 8 5 4 1 4 4
June 2O July _ 7 17 3 3 1 3 14
June 20 June 24* . . . . . . . . 12 4 . . . . . . . . . . . . . . . . . . . . . . _ ,
June 22 June 28* . . . . . . . . 24 5 . . . . . . . . . . . . . . . . . . . . . . _ _
June 22 June 29 7 15 6 2 7 O
June 22 June 27 5 1‘ 4 1 4 l
June 23 June 27* . . . . . . .. .10 4 . . . . . . . . . . . . . . . . . . . . . . _ ,
June 23 July 13 23 4 1 4 9
June 23 July 1* . . . . . . . . 22 6 . . . . . . . . . . . . . . . . . . . . . . , .
June 24 July 7 13 5 2 6 1
June 24 July 1* . . . . . . . . 54 5 . . . . . . . . . . . . . . . . . . . . . . . .
June 24 July 8 14 5 2 6 2
June 24 June 30 6 7 4 1 4 2
June 24 July 3 9 2 5 1 5 4
June 24 July 5 11 24 4 4 8 3
June 24 July 3* . . . . . . .. 14 9 . . . . . . . . . . . . . . . . . . . . . . , ,
June 25 July 10 15 5 12 2 13 2
June 25 July 3 8 34 5 2 8 0
June 26 July 1 * . . . . . . . . 45 4 . . . . . . . . . . . . . . . . . . . . . . _ ,
June 26 July 2 6 27 4 1 4 2
June 26 July 5 9 4 5 1 5 4
June 26 June 30* . . . . . .. . 31 4 . . . . . . . . . . . . . . . . . . . . . . _.
June 27 July 3 6 4 4 2 5 1
June 27 July 4 7 19 6 1 6 1
June 27 July 6 9 2 5 1 5 4
June 27 July 4 7 16 5 1 5 2
June 28 July 3 5 66 4 2 5 0
June 28 u y 2* . . . . . . . . 2O 4 . . . . . . . . . . . . . . . . . . . . . . . .
June 29 July 6 7 6 6 1 6 ' 1
June 29 July 10 11 4 4 2 6 5
June 29 Ju y 5 6 4 4 1 4 2
June 29 July 5 6 7 5 1 5 1
June 29 July 4 5 1 4 1 4 l
June 29 Ju y 6 7 13 4 2 7 O
June 3O July 5 5 9 5 1 5 O
June 3O July 6 6 14 4 2 6 0
June 3O July 6 6 1 5 1 5 1
June 30 July 1O 10 5 9 1 9 1
June 3O July 9 9 1 8 1 8 1
June 3O July 1O 10 6 5 1 5 5
June 3O July 10 1O 5 9 2 1O O
June 3O July 9 9 1 9 1 9 0
June 30 July 7 7 31 6 2 7 0
June 3O July 5 5 36 5 1 5 O
une 3O July 7 7 _ 4 7 1 7 O
1 July 8 7 74 5 2 6 1
1 July 7 6 7 5 1 5 1
1 July 13 12 9 9 2 10 2
1 July 12 11 3 5 2 8 3
1 July 11 1O 2O 4 3 9 1
1 July 8 7 11 5 1 5 2
1 July 8 7 16 4 2 7 O
1 July 9 8 1 4 1 4 4
1 July 8 7 11 4 2 6 1
1 July 6 5 6 5 1 5 O
1 July 6 5 36 5 1 5 0
2 July 7 5 2 5 1 5 O
2 July 8 6 12 5 1 5 1
2 July 7 5 20 4 1 4 1
2 July 1O 8 1l 4 3 6 2
2 July 9 7 1 4 1 4 3
2 July 11 9 1 5 1 5 4
2 July 8 6 1 5 1 5 1
3 July 9 6 18 5 1 5 1

*Indicates moth escaped or was killed before record was completed.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 43

Table l6.——Summary of the oviposition records of the first-generatioumoths of the pecan
nut case bearer. College Statlon, Texas. 1922.——Cont1nued.

.2 s-{E w '-»-> . m m ‘H _ o .
 a f»  are  5e:
g f: .._ 57,‘, o ewe; c.2933 cad-E 13:»;
MN}, 2g»  ° 2,1 $188 He: “F1133 egg
NW“ °== a e m Ewe 2521a 32w ewe
BS 8'3 a T» @825 “as E823 e25
q; q Q o O 514-1 u.) g O gm o o
Q Q .4 [-1 Z Z Z .4
b7 . . . . . . . . . . . .. July 3 July l0 7 12 7 1 7 0

68 . . . . . . . . . . . .. July 3 July 11 8 l6 6 2 7 1

69 . . . . . . . . . . . .. July 3 July 1O 7 25 4 3 7 O

70 . . . . . . . . . . . .. July 3 July 5 3 5 l 5 0

71 . . . . . . . . . . . .. July 4 July 10 6 3 4 2 6 0

72 . . . . . . . . . . . .. July 4 July 11 7 16 7 1 7 0

73 . . . . . . . . . . . .. July 4 July 15 11 47 4 5 1O 1

74 . . . . . . . . . . . .. July 4 July 11 .7 3 6 1 6 l

75 , . . . . . . . . .. July 4 July 11 7 1 4 1 4 3

76 . . . . . . . . . . . .. July 4 July 8 4 3 4 1 4 0

77 . . . . . . . . . . . .. July 4 July 18 14 1 8 1 8 6

78 . . . . . . . . . . . . . July 5 July 10 5 34 5 1 5 0

79 . . . . . . . . . . . .. July 5 July 11 ' 6 32 5 1 5 1

80 . . . . . . . . . . . . . July 5 July 12 7 60 4 4 7 0

81 . . . . . . . . . . . .. July 6 July 12 6 56 4 3 6 0

82 . . . . . . . . . . . .. July 6 July 16 10 33 4 4 7 3

83 . . . . . . . . . . . .. July 6 July 11 5 15 4 1 4 1

84 . . . . . . . . . . . .. July 6 July 11 5 37 4 2 5 O

85 . . . . . . . . . . . .. July 6 July 13 7 3 4 2 7 0

86 . . . . . . . . . . . .. July 6 July 18 12 12 4 2 11 1

87 . . . . . . . . . . . .. July 7 July 11 4 35 4 1 4 0

88 . . . . . . . . . . . .. July 7 July 13 6 1 4 1 4 2

89 . . . . . . . . . . . .. July 11 July 15 4 16 2 1 2 2

90 . . . . . . . . . . . .. July 15 July 18 3 2 3 1 3 0

In 1922 deposition records were obtained on 90 moths. The number
which oviposited was a small part of the number Which was caged
on the trees. The length of life of the females which oviposited was
7.5 days; the number of days from emergence to first oviposition was
4.9 days. Oviposition occurred over an average period of 1.5 days
for each female. From emergence to the last oviposition an average
of 5.8 days elapsed and the moths lived an average period of 1.6 days
after oviposition. _

In 1923 oviposition records were obtained on 78 moths. The largest
number of eggs laid by any individual was 143; and from dissections
made of female moths it is presumed that this is nearer the average
number than most of. the records which were obtained in captivity.

The average length of life of thefemales which oviposited Was 7
days; an average of 4 days elapsed from the time of emergence to
first oviposition. Oviposition occurred over an average period of 2 days.
From the time of emergence to the last oviposition an average of 5.7
days elapsed and the moths lived an average of 1.4 days after the last
oviposition.

411 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 17. Summary of the oviposition records of the first-generation moths of the pecan
nut case bearer. College Station, Texas. 1923
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3 A ":1 23 321:5 2:8. 2:625 511,8
g .. 2 av, gale-z cow new; “w:
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Moth ‘B: 2e‘ 1: Z” a $8. vai; v o8 :53.
Number o a w: a af fig"; g i"; s g E g‘; as;
‘gr: 13G g g o 5:: 0Q , oOO ,4; 8c 3<o
f3 Q A E—< Z Z Z A
l . . . . . . . . . . . .. June 17 June 25 8 9 8 8 0

2 . . . . . . . . . . . .. June 17 June 26* . . . . . . .. 57 4 . . . . . . . . . . . . . . . . . . . . . . ..

3 . . . . . . . . . . . .. June 17 June 28 11 54 4 4 9 2

4 . . . . . . . . . . . .. June 17 June 25* . . . . . . .. 1O 3 . . . . . . . . . . . . . . . . . . . . . . ..

5 . . . . . . . . . . . .. June 17 June 21* . . . . . . .. 3 3 . . . . . . . . . . . . . . . . . . . . . . ..

6 . . . . . . . . . . . .. June 17 June 25 8 4 3 2 7 1

7 . . . . . . . . . . . .. June 18 June 22* . . . . . . .. 12 3 . . . . . . . . . . . . . . . . . . . . . . ..

8 . . . . . . . . . . . .. June 19 June 24 5 29 3 3 5 0

9 . . . . . . . . . . . .. June 19 June 27 8 7 3 2 4 4

10 . . . . . . . . . . . .. June 19 June 25 6 11 5 2 6 O

11 . . . . . . . . . . . .. June 19 ‘June 28 9 2O 5 5 9 O

12 . . . . . . . . . . . .. June 19 June 29* . . . . . . .. 34 7 . . . . . . . . . . . . . . . . . . . . . . ..

13 . . . . . . . . . . . .. June 20 July 4 14 2 4 2 13 1

14 . . . . . . . . . . . . . June 20, June 28 8 1O 3 2 4 4

15 . . . . . . . . . . . . . June 20 June 29 9 1 6 1 6 ‘3

16 . . . . . . . . . . . .. June 2O June 24 4 11 3 2 4 O

17 . . . . . . . . . . . .. June 2O June 23* . . . . . . .. 5 3 . . . . . . . . . . . . . . . . . . . . . . ..

18 . . . . . . . . . . . .. June 21 July 3 12 4 6 3 12 0

19 . . . . . . . . . . . .. June 21 June 3O 9 42 8 1 8 1

2O . . . . . . . . . . . .. June 21 June 26* . . . . . . .. 21 4 . . . . . . . , . . . . . . . . . . . . . . ..

21 . . . . . . . . . . . .. June 21 June 25 4 1 4 1 4 O

22 . . . . . . . . . . . . . June 21 June 26 5 22 4 2 5 0

23 . . . . . . . . . . . . . June 22 July 2 1O 4 6 3 9 1

24 . . . . . . . . . . . . . June 22 June 25* . . . . . . . . 5 3 . . . . . . . . . . . . . . . . . . . . . . ..

25 . . . . . . . . . . . . . June 22 June 26 4 6O 3 2 4 O

26 . . . . . . . . . . . .. June 22 June 28* . . . . . . .. 31 4 . . . . . . . . . . . . . . . . . . . . . . ..

27 . . . . . . . . . . . . . June 22 June 28 6 36 3 3 5 1

28 . . . . . . . . . . . . . June 22 June 26 4 8 3 1 3 1

29 . . . . . . . . . . . . . June 22 July 3 11 42 4 4 9 2

3O . . . . . . . . . . . . . June 22 June 3O 8 14 3 1 3 5

31 . . . . . . . . . . . .. June 23 June 3O 7 6 3 1 3 4
. 2 July 6 13 13 3 2 8 5
June 28 5 45 3 2 4 1
July 8 15 5 4 1 4 11
June 3O 7 16 4 2 5 2
June 28 5 23 3 2 5 O
June 3O 7 78 3 4 6 1
June 3O 6 143 3 4 6 ’ 0
June 28 4 4 3 1 3 1
June 3O 6 12 4 1 4 2
June 29* . . . . . . . . 39 3 . . . . . . . . . . . . . . . . . . . . . . . .
June 27 3 6 3 1 3 O
4 June 29* . . . . . . . . 19 4 . . . . . . . . . . . . . . . . . . . . . . . .
July 3 8 24 3 4 7 1
July 1 5 28 4 2 5 O
July 9* . . . . . . . . 102 4 . . . . . . . . . . . . . . . . . . . . . . . .
July 3 6 19 4 3 6 O
July 8* . . . . . . . . 15 4 . . . . . . . . . . . . . . . . . . . . . . . .
July 4 6 21 4 . 3 6 O
July 3* . . . . . . . . 26 4 . . . . . . . . . . . . . . . . . . . . . . . .
July 4 6 54 4 3 6 O
July 4 6 3 4 1 4 2
July 4 6 1O 5 1 5 1
July 9 1O 1 4 1 4 b
July 7 8 75 4 4 7 1
July 3* . . . . . . . . 27 4 . . . . . . . . . . . . . . . . . . . . J . . .
July 8* . . . . . . . . 3O 5 . . . . . . . . . . . . . O . . . . . . . . . .
July 8 9 3 5 1 5 4
July 4 5 1 4 1 4 1
July 9 1O 6 8 2 9 1
July 8 8 45 4 5 8 O
July 5 5 7 4 1 4 1
July 7 7 19 3 3 6 1
July 8 7 2O ’ 5 1 5 2
July 7 6 76 4 3 6 O

*Indicates moth escaped or was killed before record was completed.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 45

Table 17. Summary of the oviposition records of the first-generation moths of the pecan
nut case bearer._ College Station, Texas. 1923.—Continued.

 

 

. s"  w .-,,~ . m w 1,,- . Q .
Moth g}, ‘a’ “s =gg m w, 35°: m o-E "545
Number "a 2?" s Ea raga  saga. e55
o o-—~ 0 > > >
gm gr: g’ g? gs: 5o E505’ 5E S5 $20
A A
66 . . . . . . . . . . . .. July 1 July 6* . . . . . . .. 6 I 4 . . . . . . . . . . . . . . . . . . . . . . ..

67 . . . . . . . . . . . .. July 1 July 6 5 56 5 0

68 . . . . . . . . . . . .. July 1 July 8* . . . . . . .. 18 4 . . . . . . . . . . . . . . . . . . . . . . ..

69 . . . . . . . . . . . .. July 2 July 10 8 5 6 2 7 1

7(1) . . . . . . . . . . . . . July g July 9* 6 43 é 2 5 1

. . . . . . . . . . . .. 11 l1  

72 . . . . . . . . . . . .. Jul; 5 Jul; 9* . . . . . . .. 7 4 . . . . . . . . . . . . . . . . . . . . . . ..

73 . . . . . . . . . . . .. July 6 July 16 10 3O 5 3 9 1

74 . . . . . . . . . . . .. July 6 July 11* . . . . . . .. 46 4 . . . . . . . . . . . . . . . . . . . . . . ..

75 . . . . . . . . . . . .. July 7 July 13 6 _ 18 4 1 4 2

76 . . . . . . . . . . . .. July 7 July 13 6 1 4 1 4 2

77 . . . . . . . . . . . .. July 9 July 16 7 3 4 1 4 3

78 . . . . . . . . _ . . .. July 9 July 13 4 5 4 1 4 0

*Indicates moth escaped or was killed before record was completed.
Table 18.——Length of life of the adults of the first generation. 1918-1923.
Lfeii th 1918 1920 1921 1922 1923
1 e— -

o days Male Female Male Female Male Female Male Female Male Female
1.... . 14 19 10 5 . . . . . . . . . . . . .. 1 2 1 2
2.... . 16 22 30 29 18 32 2 2 . . . . . .. 1
3.... . 28 19 32 4O 4 6 4 2 5 9
4 19 21 12 11 5 9 54 64 6 1O
5 13 10 8 12 4 7 42 53 13 17
6 4 9 6 4 2 39 56 14 19
7 . . . . . .. 2 6 . . . . . . . . . . . . . . . . . . . . . 19 34 12 18
8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1O 15 7 15
9. . . . . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4 14 5 6

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. g 2 g g

15111111111111IIIIIIIIIIIIIIIIIIIfIIIIIIIIIIIIII 1 g i, it

14II1IIIIIIIIIIlIilIfIIIIIIIIIIIIIIIIIIIIIIIfIII  1 1 2

15.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . .. 2 . . . . . .. 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 1 1

Average

length

oflife.. 3.2 ‘3 3.2 3.1 3.2 2.9 5.6 6.2 7 6.9

Maxi-

mum 9 7 7 7 6 6 14 17 16 16

Mini-

mum 1 1 1 1 2 2 1 1 1 1

Length of Life of the Adults of the First Generation

The length of life records are those of the moths which were kept in
cages. Many moths died on the first day after they emerged. The
maximum length of life varied from 6 to 1'7’ days in the several years
and was dependent 0n the care exercised in feeding the adults and

46 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

regulating the temperature in the cages. The average length of life
varied from 3 to '7 days. In the later years of the work methods of
handling the moths and regulating temperatures were developed which
account for the longer average length of life in 1922 and 1923 than
in the preceding years.

Second Generation

A second generation was recorded only in the years 1919, 1920, 1921,
and 1923. The reason for the absence of this generation in other years
is not known, but the most plausible explanation is the lack of a
supply of food.

In the years 1918, 1920 and 1922 there was an inadequate food
supply at the time the larvae of this generation developed. In 1920
the second generation was very small and in that year only 20 emer-
gence records were obtained. In 1920 the larvae almost completely
destroyed the small. nuts, although a heavy crop Was set. In 1922 a
light crop of nuts was set. The trees having the greatest promise of
a crop in 1922 were the only ones on which larvae were found in the
spring of 1923. This led to the supposition that food supply is the
controlling factor in regulating the number of generations a year.

It is probable that parasitism also has a great deal to do with the
number of generations. Parasitism is a complicated factor, since there
are many primary and several secondary parasites. Further studies
may prove this to be another limiting factor. It is interesting to note
that four generations occurred whenever two generations were com-
pleted. The crop of nuts which matured was small in the years pre-
vious to those in which four generations occurred. In 1924, however,
there were four generations following a moderate crop in 1923.

Incubation of the Eggs of the Second Generation

The incubation period was obtained from eggs on the trees. A
record more nearly comparable to natural conditions could be obtained
in this way because the nuts dry up in a day or two if they are removed
from the trees. By the time the moths of the first generation are
ovipositing the nuts are from one-third to one-half grown. On this
account little opportunity is afforded the moths to oviposit in the-
center of the pistil and the eggs are laid either on top or under the
calyx, but preferably in grooves at the tips and bases of the nuts and
on the buds below the clusters.

In 1922 the incubation period was obtained on 1147 eggs. The-
minimum period of incubation was 3 days, the maximum 7 days, and
the average 4.5 days. .

In 1923 the incubation period was obtained on 1638 eggs. The
minimum period of incubation was 3 days, the maximum 6 days, and
the average 4.6 days.

47

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER

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48 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Larval Period of the Second Generation

The larvae feed on the buds below the nut- clusters (as in the first
generation) for two or three days and then enter the nuts by cutting
circular holes at their bases. Sometimes the young larvae feed on
the outer surface Where the nuts of a cluster nearly or quite touch
each other instead of feeding on the buds.

Since the nuts are from a third to one-half grown when the larvae
of this generation have hatched, one larva does not destroy as many
nuts as does a larva of the first generation.

Only the larval records of 1923 are given. Records were obtained
on 102 larvae. The minimum duration of the larval period was 20
days, the maximum duration was 51 days, and the average 33 days.

The average duration of the larval period was 8 days longer than
in the first generation and '7 days longer than in the third generation.
The average mean temperature for the larval period of the second gen-
eration was 825° F. or 2.5° F. higher than the average mean tem-
perature for the larval periods of the first and third generations.

Table 20.—Length of the larval stage. Second generation, 1923.

v Number Average Mean
Length of Larval Stage-Days of Records Temperature
20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 .9

21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 81.9

23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 80 .8

24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 80 .1

25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 81 .6

26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 83 .6

27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 » 82 .2

28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 82 .0

29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 82 .6

30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 82 .2

31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 81 .8

32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 83 .2

33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 82 .3

34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 82.5

35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 84 .2

36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 83 .4

37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 83 .4

38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 83 .4

39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 82 .4

4O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 82 .6

41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 83 .0

42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 82 .7

43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 83 .4

45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 82 .8

46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 83 .0

47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 83 .4

48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 83 .0

50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 82 .8

51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 83 .0

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , 102 82 .5

Average length of larval stage, 1923, 33 days.

Pupal Period of the Second Generation

Pupal records were obtained for the second generation in the years
1919, 1920, 1921, and 1923. In 1920, however, so few larvae were

 

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 49

found that for all practical purposes it may be considered that a
second generation was lacking.

Table 21.—Date of pupation and period over which pupation occurred. Second generation.

1919-1923.
Number of Individuals Pupating
Date of Year
Pupation Total
1919 1920 1921 1923
College Corsicana College College Winona College
July 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . 2

July 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . 3

July 17 . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . 7

July 18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 . . . . . . . . . . 1 33

July 19 . . . . . . . . . . . . . . . . . . . . 18 . . . . . . . . . . 5 25

J y 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 38 . . . . . . . . . . 4 42

July 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 . . . . . . . . . . 6 23

July 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 . . . . . . . . . . 13 24

July 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 . . . . . . . . . . 23 54

July 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 . . . . . . . . . . 19 29

July 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 . . . . . . . . . . 28 48

July 26 . . . . . . . . . . . . . . . . . . . . 2 32 . . . . . . . . . . 51 85

July 27 1 . . . . . . . . . . 2 29 3 38 73

July 28 . . . . . . . . . . . . . . . . . . . . 1 12 4 29 46

July 29 . . . . . . . . . . . . . . . . . . . . 3 13 3 29 48

July 3O . . . . . . . . . . . . . . . . . . . . 1 16 1 39 57

July 31 1 . . . . . . . . . . . . . . . . . . .. 12 2 46 61

Aug. 1 1 . . . . . . . . . . 1 7 5 21 35

Aug. 2 11 . . . . . . . . . . . . . . . . . . . . 14 1 22 48

Aug. 3 24 . . . . . . . . . . . . . . . . . . . . 17 10 19 70

Aug. 4 . . . . . . . . . . 2 25 7 28 63

Aug. 5 2 . . . . . . . . . . 1 3 16 16 38

Aug. 6 28 . . . . . . . . . . . . . . . . . . . . 1 6 21 56

Aug. 7 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6 32

Aug. 8 10 . . . . . . . . . . 1 1 16 3 31

Aug. 9 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4 34

Aug. 10 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 10

Aug. 11 2 . . . . . . . . . . 1 1 8 2 14

Aug. 12 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 13 22

Aug. 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 3

Aug. 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 6

Aug. 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . 1 1

Aug. 16 . . . . . . . . . . 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 12

Aug. 17 . . . . . . . . . . 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Aug. 18 . . . . . . . . . . 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Aug. 19 . . . . . . . . . . 40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 42

Aug. 20 . . . . . . . . . . 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 25

Aug. 21 . . . . . . . . . . 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 18

Aug. 22 . . . . . . . . . . 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 13

Aug. 23 . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Aug. 24 . . . . . . . . . . 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Aug. 25 . . . . . . . . . . 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Aug. 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1
Tota1.. 111 165 20 369 127 508 1300

- The pupal stage is passed inside the nuts as in the first generation
and the larvae close the entrance holes with excrement and frass, as
already described for that generation. The nuts in which the pupal
period is passed are firmly fastened to other nuts or to branches or
leaves to keep them from falling from the trees. The larvae of this
generation begin to pupate about July 13 and continue until the latter
part of August. The period over which pupation occurred varied con-
siderably, because of climatic conditions during the spring brood and
first generation. In'1919 the temperatures were irregular in both of
the preceding generations and pupation was delayed. Larvae and pupae

5O BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

were collected at Corsicana because of the difficulty of obtaining larvae
at College, and although these records may be considered as representa-
tive of the close of the period of pupation they are not indicative of
the beginning of pupation because a considerable number of larvaehad
pupated When the material was collected. Although it was difficult to
find larvae at College in 1919 they were plentiful at Corsicana, Where
about 1200 were collected in two days.

Temperature had risen to the point where it had little other effect
on the duration of the pupal period than to stabilize it. The duration
Table 22.—Relation of temperature to tlltiig€llfiltgig0gl of the pupal period. Second generation.

Number of Individuals Pupat-ing and Average Mean Temperature
Year
1919 1920 1921 1923 Avg.
Length of Total Mean
Pupalgtage College Corsicana College College Winona College Temp.
— ays .
Avg Avg. Avg Avg

No Mean No No Mean N0 Mean No No Mean

Temp Temp. Temp Temp
5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  2 81.0 2 81.0

6 . . . . . . . . . . . . .. 1 83.6 1 . . . . . . . . . . .. 1 81.3 2 3 80.6 8 81.3

7 . . . . . . . . . . . . .. 3 83.1 . . . . . . . . . . . . . . . . . . . . .. 8 82.3 4 6 94.0 21 86.5

8 . . . . . . . . . . . . .. 21 83.6 3 2 82.5 45 82.0 3 78 86.1 152 84.4

9 . . . . . . . . . . . . .. 30 83.7 3 10 84.1 188 82.1 45 236 85.9 512 84.2

10 . . . . . . . . . . . . . . 15 83.3 13 3 82.9 66 82 .4 26 77 85.1 200 83.8

11 . . . . . . . . . . . . .. 8 83.2 35 . . . . . . . . . . .. 3 83.5 4 17 82.7 67 82.9

12 . . . . . . . . . . . . .. 2 83.2 41 1 81.4 . . . . . . . . . . . . . . . . . . . . .. 5 83.2 49 82.9

13 . . . . . . . . . . . . . . . . . . . . . . . . . -. 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 . . . . . .

14 . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . . . . ..

15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . 1 . . . . ..

Total . . . . . .. 80 83 5 132 16 83.5 311 82 2 85 424 85 7 1048 . . . . ..
Average length of
pupal period... 9 11.6 9.2 9 9.3 9

Table 23.—Suinmary of the length of the pupal period of the pecan nut case bearer. Second
generation. 1919-1920-1921-1923.

Period _
' Date of—— During Number Pupal Period-Days
Place which of_ In-
Year First Maximum Last Pupation dividuals _ _ _
Pupation Pupation Pupation Occurred Observed Average ‘Maximum Minimum
1918*
919 College . . . . .. July 27.... Aug. 6... Aug. 12... 17 111 9 12 6-
1
Corsicana. .. Aug. 16... Aug. 19... Aug. 25... 10 165 11.6 14 6
College . . . . .. July 17. . .‘ July 17. .. Aug. 11. .. 26 20 9.2 12 8
1920i‘ July 29
1921 College . . . . .. July 13. .. July 20... Aug. 11... 30 369 9 11 6
Winona. July 27... Aug. 9... Aug. 14... 19 127 9.3 17 6
1922*
1923 College . . . . .. July 18. . . July 26. . . Aug. 27... 41 508 9 12 5
Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
*No second generation pupae. ‘rPartial second generation.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 51

‘Pupation Curve
S

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2 13cm. N560 2853 anafifioo , @2230 a=¢3EoO v2.2.0 N anafimhoO $230 ounomhofifi
5
£3 a2 =N2 . 22 a. $5
wfimhoflfi B32 we 238:2 \
..NN2|_N2l¢NN_|2NN .2302 noflwhoaoU 2.88m o5 ... oonomkoiu a. oEwH|€m ~38. N.  \

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER - 53

of the pupal period ranged from 5 to 1'7 days, and the duration of the
pupal period of 512 individuals of the 1048 recorded for the several
years was 9 days.

Emergence of the Moths of the Second Generation

The adults of the second generation begin to emerge about July
22 and emergence may continue until September 7. The males
emerge first as in the preceding generations. In 1921 and 1923 the
period of emergence was approximately the same, the larger number
of moths emerged from July 24 to August 16. Maximum emergence

a occurred at College Station on August 5 and 6 in 1921 and on August

3 in 1923. In 1919, however, emergence was delayed several days at
(lollege and much longer at Corsicana, although the emergence records
for Oorsicana are not entirely representative of field conditions, as
some moths had already emerged in the field when the larvae and pupae
were collected.

Table 25.—Summary of the emergence records of the second-generation moths of the
pecan nut case bearer. 1919-1920-1921-1923.

Period
Over
Date of- which Number Number Number
Emerg- Moths Males Females
Year Place _ ence Ob- Ob- Ob-
First Maximum Last Occurred served served served
Emergence Emergence Emergence Days
1918*
College . . . . .. Aug. 4... Aug. 14... Aug. 22.. . 19 91 52 39
_ Aug. 17
1919
College and
Corsicana. .. Aug. 4... Aug. 24... Sept. 5.. 33 725 370 355
College... .. . July 26... . . . . . . . . .. Aug. 20... 26 16 5 11
1920f
College,
Corsicana.. . . July 26.. . . . . . . . . . . . Aug. 21 . .. 27 28 l3 15
1921 College . . . . .. July 22... Aug. 5... Aug. 17... 27 784 369 415
College, ' l .
Corsicana. .
Winona. . . . . July 22.. . Aug. 4.. . Aug. 28. . . 38 978 473 505
1922*
1923 College . . . . .. July 24... Aug. 3... Sept. 7... 46 893 464 429
Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2624 1320 1304

*N0 second generation rnoths.
tPartial second generation.

..—_-,_.>E.

_‘ ~__ g

54.

BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

l 0M5

“number o rmTI/vs Dumber o? moths Number o

  
 

Emeréence €ur ve_.
Generajion

gefiond

5% i

Cifljé vaT u re-Rh‘ ~'

Juij

Fig. 13. Emergence records and temperature? for tlég second generation. College Station, ‘Texas.
1 18- 9 .

July

b)
>4;
~1-
T

August RuQUsT

\-

STUDIES ON THE BIOLOGY OFITHE PECAN NUT CASE BEARER 55

Oviposition by the Moths of the Second Generation

The moths of this generation begin to oviposit on the third or ‘fourth
night after they emerge. The eggs are deposited in the grooves on the
sides of the nuts near the tips and bases and also 0n the buds below
the hut clusters. The eggs are deposited in a few nights, one moth
depositing 62 eggs in a single night. An individual of this genera-
tion oviposited over a period of 12 days, which was the longest period
over which oviposition occurred in any generation. Oviposition records
were obtained on 64 moths; the largest number of eggs deposited by
a single female was 190. The average length of life of the females
which oviposited was 8 days; the average time over which oviposition
occurred was 2 days. An average of 6 days elapsed from the time
the adult emerged to the last egg deposition and an average of 2.2
days elapsed from the last oviposition to the death of the moth.

Table 26.—Summary of the oviposition records of the second-generation moths of the
pecan nut case bearer. College Station, Texas. 1923

Q u’?! u: ' a . y; v, ‘u q; ,
- f‘: qr" 110w 50m ' up‘
g g e g3 gggé ggég gage rvgé
-»-> a "" '5
Moth g}, *8 "s = g, m 0'53 Ea 2 53% "ad-a
Number “as 2e .= Z; gags gas: 35.2. .1153.
.. .,.=_> e — O w; "s a =>~~ a,“
‘$15 13G g“ Es 5.: 5o 5800 E5 55 $5
Q Q .4 H Z Z Z .4
1 . . . . . . . . . . . .. July 26 July 31 5 19 3 3 5 0

2 . . . . . . . . . . . .. July 26 ug. 9 99 3 3 5 4

3 . . . . . . . . . . . H11 y 28 Aug. 8 11 46 4 5 10 1

4 . . . . . . . . . . . . . July 28 Aug. 1* . . . . . . . . 74 3 . . . . . . . . . . . . . . . . . . . . . . . .

5 . . . . . . . . . . . .. July 29 Aug. 4 6 17 3 2 4 2

6 . . . . . . . . . . . . . July 29 Aug. 2* . . . . . . . . 37 3 . . . . . . . . . . . . . . . . . . . . . . . .

7 . . . . . . . . . . . .. July 29 Aug. 3 5 54 4 1 4 1

8 . . _ . . _ . . . . . .. July 29 Aug. 3 5 48 3 2 5 0

9 . . . . . . . . . . . .. July 3O Aug. 4 5 1 4 1 4 1

10 . . . . . . . . . . . . . Aug 1 Aug. 9 8 23 5 1 5 3

11 . . . . . . . . . . . .. Aug 1 Aug. 1O 9 43 7 1 7 2

12 . . . . . . . . . . . . . Aug 1 Aug. 8 7 7 4 4 7 0

13 . . . . . . . . . . . . . Aug 1 Aug. 7 6 1 4 1 4 2

14 . . . . . . . . . . . .. Aug 2 Aug. 12 1O 2 6 1 6 4

15 . . . . . . . . . . . . . Aug 2 Aug. 6 4 8' 3 1 3 1

16 . . . . . . . . . . . . . Aug 2 Aug. 8 6 1 4 1 4 2

17 . . . . . . . . . . . . . Aug 2 Aug. 8 6 6 3 1 3 3

18 . . . . . . . . . . . .. Aug 2 Aug. 12 10 81 5 5 9 1

19 . . . . . . . . . . . .. Aug 2 Aug. 10* . . . . . . .. 55 4 . . . . . . . . . . . . . . . . . . . . . . ..

2O . . . . . . . . . . . .. Aug 2 Aug. 10 8 3 6 1 6 2

21 . . . . . . . . . . . . . Aug 2 Aug. 6 4 6 3 2 4 0

22 . . . . . . . . . . . .. Aug 3 Aug. 11 8 1 6 1 6 2

23 . . . . . . . . . . . . . Aug 3 Aug. 8* . . . . . . . . 88 4 . . . . . . . . . . . . . . . . . . . . . . ..

24 . . . . . . . . . . . . . Aug 3 Aug. 7* . . . . . . . . 22 4 . . . . . . . . . . . . . . . . . . . . . . . .

25 . . . . . . . . . . . .. Aug 3 Aug 20 17 66 5 11 16 1

26 . . . . . . . . . . . . . Aug 3 Aug. 7 4 11 4 1 4 0

27 . . . . . . . . . . . .. Aug 4 Aug. 13 9 9 4 2 5 4

28 . . . . . . . . . . . .. Aug 4 Aug. 13 9 4 5 1 5 4

29 . . . . . . . . . . . .. Aug 4 Aug. 1O 6 72 4 2 5 1

3O . . . . . . . . . . . .. Aug 4 Aug. 11 7 2 4 2 5 2

31 . . . . . . . . . . . .. Aug 4 Aug. 12 8 49 4 3 6 2

32 . . . . . . . . . . . .. Aug 6 Aug. 15 9 44 4 1 4 5

33 . . . . . . . . . . . . . Aug 6 Aug. 18* . . . . . . . . 55 4 . . . . . . . . . . . . . . . . . . . . . . . .

34 . . . . . . . . . . . .. Aug 6 Aug. 14 8 3 8 1 8 0

35 . . . . . . . . . . . .. Aug 6 Aug. 11 5 26 4 1 4 1

36 . . . . . . . . . . . .. Aug 6 Aug. 22 16 52 11 1 11 5

37 . . . . . . . . . . . .. Aug 6 Aug. 12 6 36 4 2 5 1

38 . . . . . . . . . . . .. Aug 6 Aug. 12 6 1 4 1 4 2

39 . . . . . . . . . . . .. Aug 6 Aug. 18* . . . . . . .. 190 4 . . . . . . . . . . . . . . . . . . . . . . . .

*Indicates mothescaped or was killed before record was completed.

 

 

 

 

 

56 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 26. Summary of the oviposition records of the second-generation moths of the

pecan nut case bearer. College Station, Texas——Continued.

 

' "5 m ' *4 - w a: ' a .

    as.  

s e .. a. @2612 ooze? @542 ..===:~;=

Moth MED o_ Q nu, ‘A1138 h3g1: $1138 gv-lw
Number Q0 2'0 .2: Z?“ 958a. °Bo.:s v5.9a. c333
OE 0-2 a T,“ 150g; “ggas flog; are";

\—1 P-I
4O . . . . . . . . . . . . . Aug. 6 Aug. 17* . . . . . . . . 80 4 . . . . . . . . . . . . . . . . . . . . . . . .

41 . . . . . . . . . . . .. Aug. 6 Aug. 14 8 13 4 1 4 4

42 . . . . . . . . . . . .. Aug. 6 Aug. 13 7 11 4 1 4 3

43 . . . . . . . . . . . .. Aug. 6 Aug. 13 7 117 4 4 7 O

44 . . . . . . . . . . . .. Aug. 7 Aug. 14 7 41 5 1 5 2

45 . . . . . . . . . . . .. Aug. 7 Aug. 17 10 4 5 2 6 4

46 . . . . . . . . . . . . . Aug 7 Aug. 12* . . . . . . . . 44 4 . . . . . . . . . . . . . . . . . . . . . . . .

47 . . . . . . . . . . . .. Aug. 7 Aug. 11 4 9 4 1 4 O

48 . . . . . . . . . . . ..Aug. 7Aug.12* . . . - . . . .. 28 4  . . . . ..

49 . . . . . . . . . . . .. Aug. 7 Aug. 17 1O 18 4 2 5 5

50 . . . . . . . . . . . .. Aug. 7 Aug. 19 12 124 5 6 10 2

51 . . . . . . . . . . . .. Aug. 8 Aug. 14 6 21 4 3 6 0

52 . . . . . . . . . . . .. Aug. 8 Aug. 14 6 24 4 2 5 1

53 . . . . . . . . . . . .. Aug. 8 Aug. 18 10 28 5 3 9 1

54 . . . . . . . . . . . .. Aug. 9 Aug. 17 8 2 4 1 4 4

55 . . . . . . . . . . . . . Aug. 9 Aug. 13* . . . . . . . . 42 4 . . . . . . . . . . . . . . . . . . . . . . . .

56 . . . . . . . . . . . .. Aug. 9 Aug. 17 8 83 4 4 8 O

57 . . . . . . . . . . . . . Aug 1O Aug. 26 16 1 4 1 4 12

58 . . . . . . . . . . . .. Aug. 1O Aug. 21 11 3O 4 2 11 O

59 . . . . . . . . . . . .. Aug. 10 Aug. 15 5 58 4 1 4 1

60 . . . . . . . . . . . . . Aug 10 Aug. 15* . . . . . . . . 25 5 . . . . . . . . . . . . . . . . . . . . . . . .

61 . . . . . . . . . . . .. Aug 10 Aug. 16 6 75 4 3 6 0

62 . . . . . . . . . . . . . Aug 13 Aug. 23* . . . . . . . . 148 4 . . . . . . . . . . . . . . . . . . . . . . . .

63 . . . . . . . . . . . .. Aug 15 Aug. 3O 15 1 8 1 8 7

64 . . . . . . . . . . . .. Aug 16 Aug. 3O 14 3 11 1 11 3
*Indicates moth escaped or was killed before record was completed. _
Table 27.—Length of _-life of the adults of the second generation. 1918-1923.
L h f LT 1919 1921 1923
engt o 1 e-—
Days
Male Female Male Female Male Female
1 . . . . . . . . . . . . . . . . . . 2 . . . . . . . . . .

2 . . . . . . . . . . . . . . . . . . 3 1

3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

4 . . . . . . . . . . . . . . . . . . 26 26

5 . . . . . . . . . . . . . . . . . . 36 48

6 . . . . . . . . . . . . . . . . . . 29 33

7 . . . . . . . . . . . . . . . . . . 13 16

8 . . . . . . . . . . . . . . . . . . 8 21

9 . . . . . . . . . . . . . . . . . . 9 7

10 . . . . . . . . . . . . . . . . . . 5 8

11 . . . . . . . . . . . . . . . . . . 4 7

12 . . . . . . . . . . . . . . . . . . 3 7

13 . . . . . . . . . . . . . . . . . . 3 5

14 . . . . . . . . . . . . . . . . . . 3 1

1g . . . . . . . . . . . . . . . . . . 2 g

17 . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .

18 . . . . . . . . . . . . . . . . . . 1 2

21 . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . .

gig . . . . . . . . . . . . . . . . . . 1 1
Average length of life. 4.5 4.7 2.6 2.6 6.9 7.1
Maximum . . . . . . . . . . . 13 14 4 4 25 25
Minimum . . . . . . . . . . . 1 1 1 1 1 2

 

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 57

Length 0f Life of the Adults of the Second Generation

The length of life of the adults was determined from those kept in
captivity, in cages. On account of the usual high temperatures at the
time this generation of moths appear, the life is rather short. The
average length of the life of 604 moths in 19.19 Was 4.5 days; of 271
moths in 1921 was 2.6 days, and of 340 moths in 1923 was 7 days.

Third Generation

There Was a completed third generation in 1919, 1921, and 1923, l

or in the same years when there was a completed second generation.
There may be as many larvae in this generation as in the first and
second but the number of moths was usually smaller because part of
the larvae of this generation spin overwintering hibernacula. Some
larvae of this generation enter the nuts to feed as in the two preceding
generations but most of them either feed in protected places where
two or three nuts touch at their bases or feed within the shucks.

The second and third generations overlap and each occupies a longer
period of time than the first generation.

Table 28.—-Length of incubation of the eggs of the third generation, pecan nut case bearer.
- College Station, Texas. 1923.

 

I Incubation Period——Days
D_ate of Number 3 4 5 7 Aver-
Oviposition tjEggs age

Avg. Avg. Avg. Avg. Days

N0. Mean No. Mean No. Mean No. Mean

Temp. Temp. Temp. Temp.

July 29 . . . . . . . 64 4.0

July 3O . . . . . . . 40 4.0

July 31 . . . . . . . 68 3.0

Aug. 1 . . . . . . . 71 4.0

Aug. 2 . . . . . . . 20 4.0

Aug. 3 . . . . . . . 19 5 .0

Aug. 5 . . . . . . . 5 .0

Aug. 6 . . . . . . . 23 4.0

Aug. 7 . . . . . . . 143 4.0

Aug. 8 . . . . . . . 160 4.0

Aug. 9 . . . . . . . 63 4.0

Aug. 1O . . . . . . . 317 4.0

Aug. 11 . . . . . .. 117 .1 4.0

Aug. 12 . . . . . . . 94 .1 4.0

Aug. 13 . . . . . .. 127 .8 4.4 _

Aug. 14 . . . . . . . 9 .1 4.3

Aug. 15 . . . . . .. 96 .4 4.3

Aug. 16 . . . . . . . 11 .8 5.0

Aug. 17 . . . . . .. 149 . . . . . . . . . . .. 144 84.6 5 84.1 . . . . . . . . . . .. 4.0

Aug 18 . . . . . .. 11 . . . . . . . . . . .. 11 83.6 . . . . . . . . . . . . . . . . . . . . . . .. 4.0

Aug 21 . . . . . .. 54 . . . . . . . . . . .. 27 79.2 27 78 6 . . . . . . . . . . .. 4.5

Aug 22 . . . . . .. 13 . . . . . . . . . . .. 13 77.7 . . . . . . . . . . . . . . . . . . . . . . .. 4.0

Aug 23 . . . . . .. 52 . . . . . . . . . . .. 52 77.3 . . . . . . . . . . . . . . . . . . . . . . .. 4.0

Total . . . . .. 1812 87 87 1 1510 83 5 210 82 9 5 86 5 4.0

Temperature which has a stabilizing efiect on the various stages of
the insect in the first and second generations again fluctuated as dur-
ing the development of the spring brood but to a lesser extent. For
that reason the duration of the different stages is not as constant in
the third as in the first and second generations.

58 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Incubation of the Eggs of the Third Generation

The incubation period in the third generation was- 4 days and was
determined from eggs deposited by free-flying moths and also from
moths which were kept in cages. These cages were placed on the
trees each evening and removed again in the morning. Records were
obtained on 1812 eggs; The minimum duration of the egg stage was
3 days and the maximum '7 days. Temperatures were higher during
the incubation period in this generation ‘than in the two preceding.

Larval Period of the Third Generation

After hatching from the eggs the young larvae usually hunt a pro-
tected place and begin feeding, either Where two or three nut-s touch
or on the buds below the nut clusters. The feeding habits of the partly
grown _larvae of this generation vary considerably. Some larvae enter
the nuts at their bases as in the two preceding generations and hollow
out the interior; others feed at the bases of nut clusters on the shucks
or tunnel about in the shucks next to the nuts but do not cut through
the shell.

The length of the larvel period as determined on 44 individuals
varied from a minimum of 17 to a maximum of 38 days, the average
being 26 days. The mean temperature for the average duration of the
larval period was 80° F. and this period was '7 days shorter than in
the previous generation when the mean temperature for the average

duration of the larval period was 825° F.‘

Table 29.—Length of the larval stage. Third generation. 1923.

Number of Average Mean
Length of Larval Stage—Days Records Temperature
17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 .8

18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 81 .4

19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 .5

21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 80 .3

22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 81 .8

23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 79 .9

24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 79 .3

26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 79 9

27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 80 1

' 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2 80.0

29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 80 .3

30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ 2 80 .2

31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 79 9

32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 9

33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 3

34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 0

35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 6

36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 79 .6

38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 78.9

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 80 0

Average length of larval stage, 1923, 26 days.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 59

Pupae of the Third Generation

The pupal period of the third generation is passed within the case
or cocoon spun by the larva inside'of the larval burrow. The cocoon
may be found Within the interior of the nut or in the shuck or at the
bases of several nuts, depending upon Where the larval development
has taken place. The average length of the pupal period of the third
generation is greater and more variable than in the two preceding
generations but is not as great nor as variable as the pupal period of
the spring brood.

Table 30.—-Date of pupation and period over which pupation occurred.

Third generation.
1919-1921-1923. .

Number of Individuals
Pupating
Year
Date of Pupation 1919 1921 1923 Total
College College, College
. . . . . . . . . . . . . . . . . . . . 1 1

. . . . . . . . . . . . . . . . . . . . 1 1

. . . . . . . . . . . . . . . . . . . . 4 4

. . . . . . . . . . . . . . . . . . . . 4 4

. . . . . . . . . . . . . . . . . . . . 3 3

. . . . . . . . . . . . . . . . . . . . 11 11

. . . . . . . . . . . . . . . . . . . . 14 14

. . . . . . . . . . . . . . . . . . . . 21 21

. . . . . . . . . . . . . . . . . . . . 34 34

. . . . . . . . . . . . . . . . . . . . 18 18

. . . . . . . . . . . . . . . . . . . . 27 27

. . . . . . . . . . . . . . . . . . . . 15 15

. . . . . . . . . . . . . . . . . . . . 12 12

. . . . . . . . . . . . . . . . . . . . 2O 20

. . . . . . . . . . . . . . . . . . . . 14 14

. . . . . . . . . . . . . . . . . . . . 19 19

. . . . . . . . . . 24 7 31

. . . . . . . . . . 37 17 54

. . . . . . . . . . 25 2O 45

. . . . . V . . . . 14 19 33

. . . . . . . . . . 14 5 19
4 21 10 35
12 25 6 43
2 32 14 48
10 20 9 39
7 19 12 38
11 11 6 28
4 9 3 16
7 7 . . . . . . . . . . 14
3 1 7 ' 11
6 . . . . . . . . . . . . . . . . . . . . 6
4 2 . . . . . . . . . . 6
2 2 2 6
5 . . . . . . . . . . 1 6

11 r . . . . . . . . . . . . . . . . . . . . 11

10 . . . . . . . . . . . . . . . . . . . . 10

6 . . . . . . . . . . . . . . . . . . . . 6

10 . . . . . . . . . . . . . . . . . . . . 10

10 . . . . . . _ . . . . . . . . . . . . . 10

13 . . . . . . . . . . . . . . . . . . . . 13

2 . . . . . . . . . . . . . . . . . . . . 2

2 . . . . . . . . . . . . . . . . . . . . 2

4 . . . . . . . . . . . . . . . . . . . . 4

4 . . . . . . . . . . . . . . . . . . . . 4

1 . . . . . . . . . . . . . . . . . . . . 1

1 . . . . . . . . . . . . . . . . . . . . 1

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 263 356 770

60 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 31.——Relation of temperature to the duration of the pupal period. Third generation.
1919-1921-1923.

Number of Individuals Pupating and
Average Mean Temperatures
Year
1919 1921 1923
Length of Pupal Average
Stage—Days College College College Total Mean
Temp.
Average Average _ Average
No. Mean No. Mean N0. Mean
Temp. Temp. Temp.
6 . . . . . . . . . . . . . . . . . . . 1 77 5 3 82. 7 . . . . . . . . . . . . . . 4 81.4

7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 83.1 . . . . . . . . . . . . . . 18 83. 1

8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 22 82.8 1 78.0 23 82.6

9 . . . . . . . . . . . . . . . . . .. 1 75.1 47 82.9 3 77.5 51 82.4

10 . . . . . . . . . . . . . . . . . .. 3 77.0 81 82.8 78.5 93 82.2

11 . . . . . . . . . . . . . . . . . .. 22 76.9 24 81.6 20 78.1 66 79.0

12 . . . . . . . . . . . . . . . . . .. 34 76.1 5 80.0 83 77.6 122 77.3

13 . . . . . . . . . . . . . . . . . .. 23 74. 8 7 78.3 122 77.3 152 77.0

14 . . . . . . . . . . . . . . . . . .. 14 73.5 . . . . . . . . . . . . .. 47 76.5 61 75 8

15 . . . . . . . . . . . . . . . . . .. 413 71.7 . . . . . . . . . . . . .. 5 76.1 18 72 9

16 . . . . . . . . . . . . . . . . . . . -8 70. 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 70 6

17 . . . . . . . . . . . . . . . . . .. 5 70.8 . . . . . . . . . . . . .. 1 768 6 71.8

18 . . . . . . . . . . . . . . . . . . . 1 71. 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 71 3

Total . . . . . . . . . . . . 125 74 6 207 82 5 291 77 3 623
Average length of
pupal period. . .. 12.9 9.5 12.6

Table 32.—-Summary of the length of the pupal period of the pecan nut case bearer.
_ Third generation. 1918-1923.

Period
' Over
Date of- which No. Length Pupal Stage
Pupa- Individ- —Days
Year Place First Max. Last tion uals
Pupa- Pupa- Pupa- Occurred Ob- _
tion tion tion Days served Avg. Max. Min.
1918* College . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

1919 College . . . . . . .. Sept. 17 Oct. 5 Oct. 11 25 151 12.9 18 6

1920* College . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

1921 College . . . . . . . . Sept. 12 Sept. 13 Sept. 28 17 263 9.5 < 13 6

1922* College . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

1923 College . . . . . . . . Aug. 22 Sept. 4 Sept. 29 39 356 12.6 17 8

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 770 . . . . . . . . . . . . . . . . . .

*No third generation.

The range of the period over which pupation occurred given in

‘Table No. 30 is representative of field conditions for the years 1919

and 1923, but not for the year 1921. At the time the first larvae of
this generation should have been collected heavy rains flooded the
pecan lands in the Brazos and Navasota River Valleys and delayed
the collection of larvae until after some had pupated. From general
observations it is thought that the range of pupation in 1921 covered
about the same period as in 1923. Pupation began on August 22 in

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 61

‘Pupcfli on Curve,
Third Genaration

    
  
 

all Pufhlfi

mmbg’ ‘*2 F°F°e n"‘mb‘€Y “ox Pu 0e. numbar‘
Ture-

3
1
E
u

8'1 Guy flsuCohunbus. O. _  

H0906‘! Sefjeénber Qcfober F

Fig. 14. Pupal records and temperaturesl ‘ikéggthirdfgeneration. College Station, Texas,

62

BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 33.—Time of emergence of the moths of the third generation. 1919-1921-1923.

Year -
Date of ' 4
Emerg- 1919 1921 1923 Total
ence
College College College
Male Fem Total Male Fem Total Male Fem Total

Aug. 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2 2

Aug. 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

Aug. 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

Sept. 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2 2

Sept. 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0

Sept. 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 6 6

Sept. 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4 8 48

Sept. 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3 5 5

Sept. 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 5 5

Sept. 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 6 6

Sept. 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4 14 14

Sept. 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., 4 7 11 11

Sept 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 5 12 12

Sept 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 8 16 16

Sept 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13 6 19 19

Sept 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 8 19 19

Sept 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 11 20 20

Sept 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 24 35 35

Sept 16 . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . . 2 16 22 38 40

Sept 17 . . . . . . . . . . . . . . . . . . . .. 10 13 23 24 26 50 73

Sept 18 . . . . . . . . . . . . . . . . . . . .. 8 12 20 11 16 27 47

Sept 19 . . . . . . . . . . . . . . . . . . . .. 15 17 32 20 21 41 73

Sept 20 . . . . . . . . . . . . . . . . . . . .. 14 13 27 13 17 3O 57 ~

Sept 21 . . . . . . . . . . . . . . . . . . . . . 22 22 44 12 15 27 71

Sept 22 . . . . . . . . . . . . . . . . . . . . . 14 22 _36 4 9 13 49

Sept 23 . . . . . . . . . . . . . . . . . . . .. 14 19 33 11 6 17 p 50

Sept 24 . . . . . . . . . . . . . . . . . . . . . 28 24 52 6 10 16 68

Sept 25 . . . . . . . . . . . . . . . . . . . . . 13 26 39 6 12 18 57

Sept 26 . . . . . . . . . . . . . . . . . . . . . 12 2O 32 11 6 17 49

Sept 27 . . . . . . . . . . . . . . . . . . . . . 18 15 33 14 20 34 67

Sept 28 ......-. . . . . . . . . . . . . .. 19 26 45 16 18 34 79
Sept 29 8 7 15 19 12 31 9 22 31 77
Sept 30 4 2 6 2 9 11 7 20 27 44
Oct 1 4 7 11 9 20 29 8 17 25 65
Oct 2 7 8 15 2 19 21 6 8 14 50
Oct 3 7 5 12 . . . . . . . 9 9 1 3 4 25
Oct 4 4 8 12 6 12 18 . . . . . . . 9 9 39
Oct 5 15 13 28 2 6 8 1 2 3 39
Oct 6 13 15 28 2 2 4 1 . . . . . . . 1 33

Oct 7 3 10 13 . . . . . . . 7 7 . . . . . . . 2 2 22

Oct 8 3 4 7 2 . . . . . . . 2 1 1 2 11

Oct 9 8 7 15  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15

Oct 10 10 9 19 1 2 3 1 . . . . . . . 1 23

Oct 11 9 7 16 . . . . . . . 1 1 . . . . . . . . . . . . . . . . . . . . . 17

Oct 12 3 6 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Oct 13 4 11 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 16

Oct 14 4 3 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Oct 15 5 8 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Oct 16 9 5 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Oct. 17 1 3 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4

Oct. 18 6 7 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13

Oct 19 4 9 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Oct. 20 10 13 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23

Oct 21 10 7 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ._ 17

Oct 22 3 9 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Oct 23 1 3 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Oct 24 4 2 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Oct. 25 . . . . . . . 1 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Total. . . 159 189 348 234 328 562 290 372 662 1572
_ 4

Number of Moths Emerging

- eration.

there was very little.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 63

1923 and continued until September 29. In 1919 the period of pupa-
tion was delayed. This was probably due t0 the delayed second gen-
There was also an excessive amount of rainfall in 1919. Oon-
sidering the three years, 1919, 1921, and 1923, the greater number
of larvae pupated between September 1 and 26 which is probably the
period over which pupation occurs for the average year.

Temperatures again become important as a factor in determining
the length of the pupal period. In 1919 the average mean temper-
atures for the duration of the pupal period was 746° F. and the
average duration of the pupal stage was 12.9 days. In 1923 the aver-
age mean. temperature for the duration of all the pupae observed was
77.3° F. and the average duration of the pupal stage was 12.6 days.
In 1919 there was considerable rainfall during this period while in 1923
In 1921 the duration of the pupal period was
9.5 days or practically the same average length as for the first and
second generations and the. average mean temperature for the third
generation was also nearly the same.

Emergence of the Moths of the Third Generation

The time when the moths of this generation emerge is dependent
upon temperatures during the pupal period of the spring broodand of the
first generation. The first moths of this generation were emerging at
the same time the last moths of the second generation were emerging
in 1923, hence there may be some overlapping of generations. The
moths of this generation emerged over a longer period of time than

in any of the preceding generations in 1923.

emerge on August 29 in 1923.
September 29.
in 1919 the last ones did not emerge until October 25.
1923 the emergence covered about the same length of time, the larger
number emerging from September 8 to October 4.,

Table 34.—Summary of the emergence records of t e t

The last moths emerged on October 13th. in 1923, but“

The first moths began to

In 1919 the first moths emerged on

In 1921 and

bird-generation moths of the
923

pecan nut case bearer. 19 8-1 .
Date of— . Number
_ _ Days of Total Number Number
Year Place First Maximuml Last Ernerg- Number Males Females
Emergence Emergence Emergence ence Moths
1918* College... ...
1919 College... Sept. 29... oct. 5... Oct. 25... 27 34s 159 189
Oct. 6 e

1920* College... .. .
1921 College... .. Sept. 16... Sept. 24... Oct. 11 26 562 234 328
1922* College. . . .
1923 College... .. . Aug; 29 . . . Sept. 17.. Oct. 13 46 662 290 372

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1572 683 889

*No third generation moths.

64

BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Tfinsivfience Curve‘

Gcnerofion

 

PefflTuire,

Ks
Q

O

.21‘
Em

Hue“? Sepia mbcr Oero be?

Fig. 15. Emergence records and temperatliréeisgfonéglée third generation. College Station, T exas

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 65

Oviposition by the Moths of the Third Generation

The moths of this generation deposit their eggs in grooves on the
sides of nuts and on buds below the clusters as in the two preceding
generations. Oviposition begins from 4 to 9 days after emergence,
depending on the temperature.

It was diflicult to get moths of this generation to oviposit in cap-
tivity on trees when the nights were cool, but if the moths were caged
and placed in a room where a temperature of 75° F. was maintained
they oviposited readily. Under such conditions a large number of
eggs were deposited by single moths. In 1921 when the temperatures
were high they oviposited readily. In 1923 the minimum tempera-
tures were so low that it was necessary to remove the moths to a room
Where more favorable conditions prevailed.

Oviposition records were obtained from '73 females in 1923. The
largest number of eggs laid by a single female was 247. The average
length of life of the 73 females which laid eggs was 11.8 days. From
emergence to first oviposition an average of 7 days elapsed. Ovi-
position occurred over an average of 2.3 days. From emergence to
last oviposition an average of 8.8 days occurred and the average length
of life after last oviposition was 3 days.

Table 35.—Summary of the oviposition records of the third-generation moths of the
pecan nut case bearer. College Station, Texas. 192 .

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1 . . . . . . . . . . . .. Sept 3 Sept 20 17 139 10 3 12 5

2 . . . . . . . . . . . .. Sept 5 Sept 21 16 5 10 6 15 1

3 . . . . . . . . . . . .. Sept 5 Sept 25 2O 68 7 5 11 9

4 . . . . . . . . . . . .. Sept 5 Sept 19 14 247 6 5 13 1

5 . . . . . . . . . . . .. Sept 8 Sept 23 15 208 9 14 1

b . . . . . . . . . . . .. Sept 9 Sept. 30 21 17 11 2 12 9

7 . . . . . . . . . . . .. Sept 9 Sept. 21 12 1 5 1 5 7

8 . . . . . . . . . . . .. Sept 1O Sept 15* . . . . . . . . 78 4 . . . . . . . . . . . . . . . . . . . . ..

. . . . . . . . . . . .. Sept 1O Sept 23 13 10 6 1 6 7

1O . . . . . . . . . . . .. Sept 10 Sept 29 19 13 14 2 17 2

11 . . . . . . . . . . . .. Sept 1O Sept 14 1O 1 1O 4

12 . . . . . . . . . . . . . Sept 1O Sept 28* . . . . . . . . 33 8 . . . . . . . . . . . . . . . . . . . . . .

13 . . . . . . . . . . . .. Sept 11 Sept 25 14 12 1 12 2

14 . . . . . . . . . . . .. Sept 11 Sept 24 13 101 4 4 9 ,4

15 . . . . . . . . . . . .. Sept 11 Sept 2O 8 1 8 1

16 . . . . . . . . . . . .. Sept 11 Sept 28 17 64 16 1 16 1

17 . . . . . . . . . . . .. Sept 12 Sept 25 13 22 4 3 7 6

18 . . . . . . . . . . . .. Sept 13 Sept 23 1O 9 4 3 7 3

19 . . . . . . . . . . . .. Sept 13 Sept 20 18 4 2 5 2

2O . . . . . . . . . . . .. Sept 13 Sept 24 11 13 8 2 10 1

21 . . . . . . . . . . . .. Sept 13 Sept 23 1O 2 3 1 3 7

22 . . . . . . . . . . . . . Sept. 14 Sept 28 14 1 5 1 5 9

23 . . . . . . . . . . . . . Sept. 14 Oct 18 17 1 17 1

24 . . . . . . . . . . . .. Sept 15 Oct 1 16 123 4 7 12 4

25 . . . . . . . . . . . . . Sept 15 Sept 25 1O 4 2 8 2

26 . . . . . . . . . . . . . Sept 15 Sept 24 9 20 7 2 9 0

27 . . . . . . . . . . . . . Sept. 15 Sept. 28 13 3 1O 1 .10 3

28 . . . . . . . . . . . . . Sept. 15 Sept. 20* . . . . . . . . 20 5 . . . . . . . . . . . . . . . . . . . . . . . .

29 . . . . . . . . . . . . . Sept. 15 Sept. 24 9 20 5 2 7 2

*Indicates moth escaped or was killed before record was completed.

66 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Table 35. Summary of the oviposition records of the third-generation moths of the pecan
nut case bearer. College Station, Texas. 1923—Continued,

' '75 v: ' -*-’ - m ' . .
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gm gm g fig? i: 5o §€5o Ea: 55 33°25
Q Q A E-' Z Z Z Q
30 . . . . . . . . . . . . . Sept. 15 Sept 28 13 36 6 4 9 4‘

31 . . . . . . . . . . . . . Sept. 15 Sep 28 13 1 7 1 7 6

32 . . . . . . . . . . . . . Sept. 16 Oct. 17 53 1O 2 11 6

33 . . . . . . . . . . . . . Sept. 16 Sept 28 12 4 6 1 6 6

34 . . . . . . . . . . . . . Sept. 16 Sept 28 12 1 1 6 6

35 . . . . . . . . . . . . . Sept. 16 Oct 18 48 14 1 14 4

36 . . . . . . . . . . . . . Sept. 16 Sept 24 1 1 6 2

37 . . . . . . . _ . . . .. Sept. 17 Sept 28 11 1 10 1 10 1

38 . . . . . . . . . . . . . Sept. 17 Sept 30 13 45 5 2 10 3

39 . . . . . . . . . . . . . Sept. 17 Sept 24 7 12 5 2 6 1

4O . . . . . . . . . . . . . Sept. 17 Sept 28 11 5 3 9 2

41 . . . . . . . . . . . . . Sept. 18 Sept 28 10 1 8 1 8 2

42 . . . . . . . . . . . .. Sept.~18 Sept 28 10 2 6 1 6 4

43 . . . . . . . . . . . . . Sept. 18 Oct 4 16 25 9 3 11 5

44 . . . . . . . . . . . . . Sept. 18 Sept 28 10 21 6 2 9 1

45 . . . . . . . . . . . . . Sept. 18 Sept 29 11 1 1O 1 1O 1

46 . . . . . . . . . . . . . Sept. 19 Sept 28 9 29 5 4 8 1

47 . . . . . . . . . . . . . Sept. 19 Sept 28 9 25 5 2 6 3

48 . . . . . . . . . . . . . Sept. 19 Sept 24 5 60 5 1 5 0

49 . . . . . . . . . . . .. Sept. 19 Sept 24 5 5 1 5 O -

50 . . . . . . . . . . . . . Sept. 19 Oct. 4 15 12 5 6 14 1

51 . . . . . . . . . . . .. ept. 19 Sept 29 10 3 6 3 10 0

52 . . . . . . . . . . . . . Sept. 19 Sept 29 1O 11 5 4 8 2

53 . . . . . . . . . . . . . Sept. 2O Sept 3O 1O 42 7 4 1O O

54 - . . . . . . . . . . . . Sept. 20 Sept 28 8 13 5 1 5 3

55 . . . . . . . . . . . . . Sept. 21 Oct 6 15 9 9 3 12 3

56 . . . . . . . . . . . . . Sept. 21 Oct 2 11 1 1O 1 1O 1

57 . . . . . . . . . . . . . ept. 22 Oct. 2 1O 34 6 2 7 3

58 . . . . . . . . . . . . . Sept. 23 Sept. 30* . . . . . . . . 25 5 . . . . . . . . . . . . . . . . . . . . . . . .

59 . . . . . . . . . . . . . Sept. 23 Oct. 5 12 36 8 4 11 1

6O . . . . . . . . . . . . . Sept. 23 Oct 5 12 22 6 4 12 O

61 . . . . . . . . . . . . . Sept. 23 Oct 9 14 2 7 2 9 5

62 . . . . . . . . . . . . . Sept. 24 Oct 1 7 1 6 1 6 1

63 . . . . . . . . . . . . . Sept. 24 Oct 1 7 5 6 1 6 1

64 . . . . . . . . . . . . . Sept. 28 Oct 8 1O 12 5 1 5 5

65 . . . . . . . . . . . . . Sept. 28 Oct 4 6 1O 4 2 6 O

66 . . . . . . . . . . . . . Sept. 29 Oct 6 7 47 4 2 5 2

67 . . . . . . . . . . . . . Sept. 30 Oct 18 18 1 5 1 5 13

68 . . . . . . . . . . . . . Sept. 3O Oct 10 1O 7 1 7 3

69 . . . . . . . . . . . .. Sept. 30 Oct 12 12 15 7 3 10 - 2

70 . . . . . . . . . . . . . Sept. 30 Oct 8 8 12 7 2 8 0

71 . . . . . . . . . . . . . Oct. Oct 11 9 3 4 3 7 2

72 . . . . . . . . . . . . . Oct. 4 Oct. 18 14 28 6 3 1O 4.

73 . . . . . . . . . . . .. Oct. 4 Oct. 11 12 6 1 6 1

*Indicates moth escaped or was killed before record was completed.

Length of Life 0f the Adults of the Third Generation

The life of the adults of the third generation was longer than that
of the three preceding generations. The average length of life in
1919 was 4.7 days and 8.8 days in 1923. The longer period in 1923
Was due to the fact that the methods of feeding and rearing the adults
had been improved over those of 1919. The adults do not thrive in
captivity and are difficult both to feed and handle. The males usually
die before the females.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 67
Table 36.——Length of life of the adults of the third generation. 1919-1923.
_ 1919 1923
Length of Life——Days
Male Female Male Female
1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 2 1

2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 17 . . . . . . . . . . . . . . . . . . . .

3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5 . . . . . . . . . . . . . . . . . . . .

4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 7 13

5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 15 23

6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 8 19 21

7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 12 14 19

8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 11 19

9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 6 13

10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 9 19

11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3 5 12

12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 18

13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . 2 8

14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7

15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5

16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4

18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2

21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . . ".

Average length of life . . . . . . . . . . . . . . . . 4 .6 4.8 8 9 .2

Maximum . . . . . . . . . . . . . . . . . . . . . . . . . . 13 11 23 21

Minimum . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1 1

Table 37-—Length of incubation of the eg s of the fourth generation pecan nut case

bearer. College tation, Texas. 1923.
Incubation Peri0d—Days
Date of 4 5 6 7 Average
O_vip0- No. Days
sition Eggs Average Average Average Average
No. Mean No. ean N0. Mean No. ean
Temp Temp. Temp. Temp.
Sept. 11 76 . . . . . . . . . . . . .. 76 79.3 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5

Sept. 12 49 . . . . . . . . . . . . . . 49 78.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . _ 5

Sept. 13 90 7 77.7 83 77.9 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.9

Sept. 14 93 66 77.6 27 78.4 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.2

Sept. 15 134 . . . . . . . . . . . . .. 134 78.9 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5

Sept. 16 165 89 79.0 76 77 .3 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.4

Sept. 17 46 . . . . . . . . . . . . .. 21 76.3 25 75.0 . . . . . . . . . . . . .. 5.5

Sept. 18 98 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 78 73.9 20 74.1 6.2

Sept. 19 36 . . . . . . . . . . . . .. 4 72. 32 72 .9 . . . . . . . . . . . . .. 5.9

Sept. 20 103 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 72 .8 . . . . . . . . . . . . . . 6

Sept. 22 120 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 76 .0 . . . . . . . . . . . . . . 6

Sept. 23 20 . . . . . . . . . . . . . . 20 77 .4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sept. 25 38 . . . . . . . . . . . . . . 38 79.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sept. 27 36 13 78.5 . . . . . . . . . . . . .. 23 78.6 . . . . . . . . . . . . .. 5.2

Sept. 28 53 13 79.1 40 78 .9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7

Sept. 29 23 . . . . . . . . . . . . . . 23 78 .7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Sept 30 62 . . . . . . . . . . . . . . 62 78 .3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Oct. 1 11 . . . . . . . . . . . . .. 11 76.2 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5

Oct. 2 18 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18 74.1 . . . . . . . . . . . . .. 6

Oct. 3; 16 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16 73.6 . . . . . . . . . . . . .. 6
Total. . . 1287 188 78.4 664 78.3 415 74.5 20 74.1 5.2

68 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

Fourth Generation

The fourth generation, which is not completed until the following
spring, is represented by the egg and larval stages only. The larvae
feed for a short time after hatching on the shucks if they are still on
the trees. If none are available they feed at the bases of the leaf
petioles and on buds, after which the larvae spin hibernacula. The
latest date a larva was observed to be feeding was November 11.

Incubation of the Eggs of the Fourth Generation

The duration of the egg stage is dependent on temperature, in 1923
the minimum duration being 4 days, the maximum '7 days, and the
average duration 5.2 days. The larvae which hatch from these eggs
spin hibernacula in which they pass the winter. In the spring they
are known as spring brood larvae.

SUMMARY

The pecan nut case bearer passes the Winter in the larval stage in
a. tough silken hibernaculum which is made by the larva. This hiber-
naculum is saucer-shaped and about 3 mm. in diameter.

As soon as tree growth starts in the spring the larvae become active
and begin t0 feed on the buds to which the hibernacula are attached.
After feeding within the hibernaculum for some time the larva deserts
it and enters the new growth at the axils ofleaf stems. A burrow is
made on the interior of the tender growth within which the larval
period of the spring brood is passed. The point of entrance may be
determined by the frass and excrement which the larva throws out.
The larvae are feeding in these burrows during the latter part of
March and the month of April. If the temperature is low or if there
is a great deal of cloudy and windy weather larval development is re-
tarded. After completing its growth the larva stops up the entrance
to its burrow and spins a flimsy case or cocoon within which pupation
takes place. The length of the pupal period is dependent on climatic
factors, the chief of which is probably temperature. The duration of
the pupal stage ranged from 9 to 24 days and the average length
varied from 12 to 18 days for the several years. When the daily
minimum temperature was below 65° for several days or when it
fluctuated greatly or when the mean temperature was only slightly
above 65° F., the period over which pupation occurred was from 4 to 6
days longer than when the minimum daily temperature was above 65°_F.’
Emergence of spring-brood moths is dependent upon climatic factors
during the time the insect is in the pupal stage. Low temperature,
however, is only a delaying factor, as the natural emergence usually
follows in time. The spring-brood moths emerge during the latter
half of April and the first half of May, maximum emergence occurring
between May 5 and May 13. The life of the adults is short, most of
the moths dying within five or six days after emergence.

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 69

The eggs deposited by the spring-brood moths are the beginning of
.the first generation. The eggs are usually deposited in the center of
the pistil or on the upper or lower surface of the calyx lobes. Ovi-
position begins on the third or fourth night after emergence, and is
completed in a few nights. The eggs hatch in 5 days, after which the
young larvae wander about until they have found a protected place and
begin feeding. In most cases the larvae feed upon buds for two or
three days, after which they enter the small nuts at their bases by/
cutting out circular holes. They feed on the interior of nuts, which at
this time are a little larger than an English pea. A larva goes from
one nut to another until it is full grown. Before entering a nut a
larva fastens it to other nuts or a branch by means 0' silken threads.
The length of the larval period is about 25 days. hen grown the
larva selects a dry nut and stops up the _point of entrance with silk
and excrement, after which it spins a flimsy cocoon within and pupates.
Temperature at the time this generation is passed has risen to the
point where its effect on the‘ pupal stage is less marked. The average
mean temperature of the pupal period of 884 individuals of the 1314
recorded for the six years was 80° F, and the average pupal period for

the 1314 individuals was 9 days. The minimum length of the pupal
period was 5 days and the maximum 16 days.’ The moths of this
generation begin to emerge the latter part of May or the first part

‘ of June, and emergence is completed by the first of July. They live
only a few days and begin to oviposit on the fourth or fifth night after
they emerge. .

There was a second generation only in 1919, 1920, 1921, and 1923;
and in 1920 the number of second generation moths which emerged
was negligible. It is probable that one could always find a few second
generation larvae in any year if search were made over a wide enough
territory. But continuous searching for several weeks in 1918 and
1922 did not result in the finding of any larvae of this generation.

The eggs hatch in from 3 to '7 days, the larger number hatching in
5 days. After hatching the larvae feed on the buds as in the pre-
ceding generation and then enter the bases of the nuts and feed on
the inside. The mean temperature in this gene-ration was a little
higher than tiiTthe preceding and the larval stage was longer——the
average duration being 33 days. After completing their growth the
larvae _close the openings through which they entered the nuts and
spin flimsy cocoons within, after which pupation occurs. The period
over which pupation takes place may range from July 13 to August 2'7.
The average length of the pupal period was 9 days for each of the
years 1919, 1920, 1921, and 1923. The average mean temperatures
were high in each of the three years and seemed to have a stabilizing
effect on the length of the pupal period.

The period over which the moths of the second generation emerged
ranged from July 22 to September '7, maximum emergence occurring
in two of the years between August 2 and August 6. Emergence
records were made on 2624 moths.

70 BULLETIN NO. 347, TEXAS AGRICULTURAL EXPERIMENT STATION

The adults oviposit 0n the third 0r fourth night after emergence,
in grooves on the sides of the nuts or on buds below the nut clusters.
The largest number of eggs laid by one female was 190. Because of
the hot weather the adults did not live long in the cages, the average
length of life being from 2.6 to 7.1 days.

There was a third generation only in those years when a second gen-
eration was completed. The eggs of this generation hatch in 5 days,
after which the larvae seek protected places Where several nuts touch
and begin feeding on the nuts or on buds. The larvae of this gen-
eration sometimes enter the nuts as in the two preceding generations
but most of them feed in the interior of thelshucks or on the shucks
at the bases of a cluster of nuts. The average length of the larval
period was 26 days. The average mean temperature was about the
same as in the first generation and the average duration of the larval
period Was about the same as that of the first generation. An average
mean temperature several degrees above 80° F, has the effect of
lengthening the duration of the larval stage. After completing their
growth the larvae spin cocoons in the larval burrows and pupate. The
average duration of the pupal period varies from 9.5 to 12.5 days, the
duration depending on the temperature. The time when the moths
of the third generation emerge depends on the temperature during the
pupal stage and also on the time when the previous generations have

matured. In the several years emergence varied considerably, the -

period ranging from September 29 to October 25, and from August 29
to October 8. From 4 to 9 days after emergence oviposition begins
and may continue for some time in cool weather.

The eggs hatch in from 5 to 9 days. The young larvae feed on the
shucks when available or in the axils of leaves and on the buds, later
spinning the overwintering hibernacula. Some larvae may feed as
late as the 11th of November.

 

STUDIES ON THE BIOLOGY OF THE PECAN NUT CASE BEARER 71

BIBLIOGRAPHY

(1) Busck & Heinrich.
~15 1921. On ‘the Male Genitalia of the Microlepidoptera and their Sys-
tematic Importance. Proc. Ent. Soc. of Wash. Vol. 23,
No. 6.
(2) ~Dya1', H. G.
1902. A list of North American Lepidoptera and key to the litera-
‘f’ ture of this order of insects. Bul. U. S. Nat. Mus., No. 52,
. 419.
Listeldgfrom Mass, N. Y., Illinois and Texas.
(3) Dyar, H. G.
v/ 1908. Notes on the species of Acrobasis, with descriptions of new
ones. Proc. Ent. Soc. Wash., V. 10, No. 1-2, 41-48.
Page 46: Reared specimens from Summerton, S. C.
(4.) c111, J. B.
\/ 1917. Important pecan insects and their control.
Agr., Farmers’ Bul. 843, 48 p., 58 fig.
(s) c111, J. B.
‘f 1924. Important pecan insects and their control.
Agr., Farmers’ Bul. .1364, 48 p., 61 fig.
(a) c111, J. B.
1925. The pecan nut case-bearer.
Bul. 1303, 12 p., 4 fig.
(7) Grote, A. R.
1881. Papilio, Vol. 1, No. 2, p. 13-14.
Original description.
(8) Hulst, G. D.
1890. _The Phycitidae of North America.
V. 17, p. 93-229, pl. 6-8.
Synopsis 0f species.
(9) Matz, J.
V, 1918. Diseases and insect pests of the pecan.
Bul. 147, p. 135-163, fig. 45-73.
(10) McDunnough, J. H. .
i" Barnes, William. I a '
1914. Synonymic notes on North American Lepidoptera. Contrib.
to the Nat. Hist. of the Lep. of N. Am., Vol. 2, no. 5, page 222.
Comparisons of A. caryae and A. caryivorella.
Ragonot, E. L.
1893. Monographie des Phycitinae et des Galleriinae. In Romanofi,
N. M., Memoirs sur les Lepidopteres, V. 7-8, 658-602, p. 57 pl.,
St. Petersburg and Paris.

U. S. Dept. of
U. S. Dept. of

U. S. Dept. of Agr., Department

V

Trans. Amer. Ent. 'Soc.,

Fla. Agr. Exp. Sta.

(11)

(12) Sanderson, E. D.
1904. Insects of 1903 in Texas. In Proceedings of the sixteenth an-
nual meeting of the Association of Economic Entomologists,
U. S. Dept. Agr. Div. Ent., Bul. 46, p. 95.
Page 95: Reports serious injury to pecan crop of Texas by Acrobasis
caryae. '
(13) Stiles, E. P.
1902. Pecan huskworm. In Farm and Ranch, Vol. 21, no.‘ 50, p.
10-11.
Gives account of injury in west-central Texas caused by what he calls
the pecan husk-worm but was probably the pecan nut case bearer.
(14) Zeller. a
1848. Fam. Phycidae. Acrobasis, Genus XXIX, Isis, p. 607.