B-1157
P October 1975

Texas Persimmon Distribution and
Control with Individual

i‘?  i‘? i T5376 I

FHE TEXAS A&M UNIVERSITY SYSTEM, THE TEXAS AGRICULTURAL EXPERIMENT STATION
I. E. MILLER, DIRECTOR, COLLEGE STATION, TEXAS

CONTENTS

Page
SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . 2

INTRODUCTION . . . . . . . . . . . . . . . . . . . . 3

MATERIALS AND METHODS . . . . . . . 4

Survey of the Problem . . . . . . . . . . . . 4

Control Studies . . . . . . . . . . . . . . . . . . 4

RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Extent of the Problem . . . . . . . . . . . . . 5

Control with Sprays . . . . . . . . . . . . . . 7
Control with Pelleted
Herbicides . . . . . . . . . . . . . . . . . . . . . 9
DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . 10
LITERATURE CITED . . . . . . . . . . . . . . . . . 12
ACKNOWLEDGMENTS . . . . . . . . . . . . . . 12

SUMMARY a

Texas persimmon is a hard-to-kill woody pill
infesting South Texas rangeland. Highest infestati
occur in a group of 13 counties in south-central T
from the southern edge of the Edwards Plateau’ i
the northern South Texas Plains. Although 
considered a minor component of range vegetati
Texas persimmon may become one of the pr‘ 
problems following use of mechanical brush con.
methods such as chaining and root plowing. It is‘;
sentially resistant to conventional herbicides app
as broadcast sprays. The most effective treatment l.
been application of 12 to 16 pounds of 2, 4, 5-T
100 gallons of diesel oil as a basal spray in the ho y.
part ofthe summer. However, good control of T 

persimmon resulted when silvex + picloram was

plied at 2 pounds per 100 gallons as a foliar spray or p
pounds per 100 gallons applied as a basal spray ' “
1971 to 1973. Picloram pellets were more effective
controlling Texas persimmon than were herbi »
sprays. The most effective time for application of
cloram pellets was in the spring before a rain. I
No grass damage was noted from the applica

of herbicides to the foliage. However, basal app

tions of picloram and the high rates of the pt.

completely controlled grass for 12 to 18 inches aro 

the base of treated plants. 

  
 
 
 
  
  
 
 
  
 
  
  
   
 
 
 
  
  
  
 
 
 
 
 
  

  
  
    
   
   
 
  
  
  
  
  
 
   
 
   
  
   

 
 
 
   
   
   
  
 
 
 
 
 
 
  

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INTRODUCTION

 Texas persimmon (Diospyros texana Scheele), also
called "black" and ”Mexican" persimmon (Vines,
960), is a hard-to-kill woody plant infesting Texas
p angeland. It is a shrub or small tree usually 6 to 8 feet
951311, rarely more than 20 feet. However, a tree 26 feet
;;.;tall has been reported (Meyer, 1974). Growth form
varies from plants which branch near the soil surface
(Figure 1) to those with prominent trunks (Figure 2),
but only rarely are they single stemmed. Texas per-
immon leaves are thick, leathery, dark green and
y)» or obovate. The bark usually is hard and
aracteristically splits and flakes, especially at the
e of the main trunks, revealing light grey wood.
ittle is known of the life history or biological nature
 this undesirable species or of its potential to
p» ead. However, some workers feel that Texas per-
"ii on has the potential to become in the next 25
 one of the most serious management problems
 millions of acres of Texas rangeland (Hoffman,
Texas persimmon is dioecious and produces a
, green fruit which turns black and sweet at ma-
'ty. The fruits contain hard, shiny seed about 0.3
 es long. The pulp surrounding the seed is relished
[;wild-li.fe. Seed germination is improved when the
. p is removed mechanically or if the seed are passed
r “tough the digestive tracts of animals.
 Texas persimmon is resistant to conventional ap-
l k ‘tions of the commonly-used herbicide, 2,4,5-T
(FLS-trichlorophenoxy) acetic acid], as a broadcast
ijay (Hoffman, 1972). It can be controlled with indi-
4 al plant treatments of about 16 pounds of 2,4,5-T
f 100 gallons of diesel oil applied as a basal spray
i) July through February. This is almost twice the
ficentration used to control most troublesome
 plants. However, results with this treatment
i  exas persimmon are often erratic.
The season of control of Texas persimmon has
 “correlated with energy levels in various plant
 Wilson (1969) studied carbohydrate content of
  if persimmon leaves, stems and roots throughout

‘i

1A- professor, The Texas Agricultural Experiment Station
fQepartment of Range Science, The Texas A&M University
f. '
 of a trademark or proprietary product does not constitute
 tee or warranty of the product by The Texas Agricultural
 ent Station and does not imply its approval to the exclu-
other products-that also may be suitable.

 Texas Persimmon Distribution and Control
with Individual Plant Treatments

c. ]. SCIFRES*

the season from early April to late November 1969.
Carbohydrate content of roots was always higher, re-
gardless of sampling time, than that of stems or
leaves. Carbohydrate content of the stems was usu-
ally somewhat higher than that of leaves, regardless
of season sampled. Carbohydrate levels in roots gen-
erally were lowest from the first week in ]une to the
first week in August and rapidly increased to the last
of October. Carbohydrate content of roots ranged
from 12 percent in early Iune to over 2O percent in
October. Although there was a slight increase in car-
bohydrates during the middle of May, Texas persim-
mon plants generally lost carbohydrates rapidly from
the first of April to the first of June. Wilson (1969) felt
that the low peak of carbohydrate storage and the
increase in storage during August and September
could be correlated directly with the reaction of Texas
persimmon to translocated herbicides.

Texas persimmon plants are relatively easy to de-
foliate, but roots must be killed for effective control.
Removing the tops only results in prolific sprout pro-
duction from the roots and trunk bases.

Before extensive research on the species could be
undertaken, information on distribution, range prac-
tices and sites associated with infestations of Texas
persimmon, and its response to commonly used
brush control methods, was needed. This report in-

'1!“

Figure 1. Texas persimmon plant with many branches.
Plant developed at ground line resulting in ”Bushy” growth
form.

cludes results of a survey undertaken t0 obtain these
data. After establishing the extent and severity of the
Texas persimmon problem, several herbicides, herbi-
cide combinations and formulations were evaluated
for control at various application dates.

MATERIALS AND METHODS

Survey of the Problem

Field observations indicated that about a 19-
county area in south central Texas supported the
most intense infestations of Texas persimmon} A
questionnaire was developed and sent to 75 counties
including and surrounding the area suspected of
supporting the worst infestations of Texas persim-
mon. Questionnaires were sent to county extension
agents who were encouraged to consult with Soil
Conservation Service personnel and ranchers before
completing the forms. Questions included estimates
of the percentage of the land within the county in-
fested with Texas persimmon. Provision was made
for denoting only a specific portion of the county if
necessary. Completed questionnaires were grouped
relative to acreage infested as greater than 7O percent,
5O to 69 percent, 25 to 49 percent, 5 to 24 percent, or 1
to 4 percent, and no infestation. One plant per acre
was considered an "infestation" to simplify comple-
tion of the questionnaires. These data were used to
map the primary distribution of Texas persimmon.

Other data requested in the questionnaire in-
cluded information on association of Texas persim-
mon with particular range sites, association with
range management practices, most common methods
used by ranchers for control, an estimate of the rela-

lPersonal communication. 1971. G. O. Hoffman, Exten-
sion Range Brush and Weed Control Specialist, Texas
A8M University (Department of Range Science).

4

Figure 2. Texas persimmon
plant zuith little branching
near ground line resulting in
"tree-type” growth form.

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tive importance of Texas persimmon as a brush prob-
lem in the county, and an opinion as to the possibility
of the Texas persimmon problem intensifying in thei
next 15 years. A section was provided for pertinen 
information not included in the formal questions;
Where possible, specific responses were grouped -_
presented as percentages of total answers obtained. i

Control Studies 

Research on chemical control of Texas persim
mon was located near Comfort, Texas in Kenda
County. The research area, typical of the Edwar!
Plateau, was characterized by precipitous slopes 
shallow soils with numerous rocky outcrops. In so I .
cases, depth of top soil was less than 0.75 inch in g
study area. The rocky outcrops occasionally rea 5f
boulder proportions. The stony surface overlies a 1 T
2-inch zone of clay loam to loamy soil with a calcar
ous underlayer. The heavy clay subsoil is high 
gravel content. Principle woody plants of the stud“
area are live oak (Quercus virginiana Mill.), seve l,
species of juniper (Iuniperus spp.), and Texas p
simmon. Grasses were typified by short-grass speci =2
such as Texas grama (Bouteloua rigidiseta (Steud.
Hitchc.), common curly mesquite (Hilaria belang,
(Steud.) Nash) and Texas wintergrass (Stipa leucotri 
Trin. and Rupr.). Scattered large plants of sacahuisk
(Nolina texana S. Wats.) were common. The area 
stocked with mother cows, calves, ewes and lamp;
during the course of the study.  

.“_ 3:.

Initial herbicide applications were completed  g
July 9, 1972. From results of that experiment, select
herbicides were applied on November 26, 19.-
March 13, 1973 and/or Iune 7, 1973. Herbicides w
applied with a handgun attached to a power spray
using 150 pounds per square inch with a "size 
orifice. Delivery rate was 2.21 gallons per minu 
Basal treatments were applied in diesel oil ca '

icompletely wetting the lower 18 to 24 inches of the
stems. Foliar applications were made t0 completely
wet the foliage using a diesel oilzwater (1:4) emulsion
as carrier. Herbicides were evaluated at 2 pounds per
100 gallons of carrier for foliage and 6 pounds per 100
gallons of carrier for basal treatments. I

Herbicides evaluated as foliar or basal treatments
on July 9, 1972 were 2,4-D [(2,4-dichlorophenoxy)
acetic acid], 2,4,5-T, silvex [2-(2,4,5-trichloropropi-
onic) acetic acid], dicamba (3,6-dichloro-0-anisic acid),
picloram (4-amino-3,5,6-trichloropicolinic acid),
combinations of 2,4-D + dicamba, 2,4,5-T + dicamba,
2,4-D + picloram, 2,4,5-T + picloram, and silvex
+ picloram. Dry formulations of picloram and karbuti-
late [tert-butylcarbarnic acid ester with 3-(m -hydrox-
yphenyl)-1,1-dimethylurea] were applied as pellets
based on canopy size at 0.005, 0.011 or 0.022 ounces
active ingredient per foot of canopy diameter? Can-
opy diameters were measured at a height of 4 feet.

During herbicide application, the time required
for treatment, the average amount of chemical used,
and the size of trees were recorded for reference. It
was also recorded whether or not the persimmon
plants were male or female, the general condition of
the canopy cover, and environmental variables such
as air and soil temperature and moisture.

The first study was established as a single plot for
each treatment. Each plot contained at least 27 trees
which were tagged with permanent numbers. In sub-

‘_ sequent studies, 27 trees per plot were utilized with at

' least duplicate plots of each treatment established in a I

completely random design. Reaction of Texas per-
simmon to the herbicide treatments was recorded at
either 6 months, 1 year and/or 2 years after treatment.
At 6 months after treatment, the degree of defoliation
was estimated by two workers. At 1 and 2 years after
treatment, degree of defoliation was noted and trees
completely defoliated were closely observed for the
p development of stem or root sprouts. The ground sur-
 face was checked for root sprouts within a radius of
about 6 feet from the trunk base. At each date of
evaluation, degree of grass damage also was noted.

Overall treatment performance was assessed
ibased on average percentage canopy reduction, per-
‘icentage of trees completely defoliated and not re-
 sprouting, and coefficients of variation associated with
Qeach of the herbicide treatments. Where appropriate,
Qmean. separation tests were used to make treatment
icomparisons.

4 . RESULTS
glixtent of‘ the Probljem
 The primary distribution of Texas persimmon in-

lgtjludes part or all of 50 counties in south-central and
 tes were converted t0 English system and were originally
i lied as 0.5, 1 and 2 grams active herbicide per meter of

 ‘nopy diameter, respectively.

    
 
  

Texos Persimmon Distribution ‘

   
 

Acreage
Infested (%)
7095
I 50-69
E 25-49
5-24
1-4
Figure 3. Map shows distribution of Texas persimmon on
Texas rangelands as developed from responses to 1971 sur-

vey.

south Texas (Figure 3). Most intense infestations were
reported from a group of 13 counties, including Sutton
on the west to Blanco on the east, and Llano on the
north to Medina on the south. However, significant
infestations were reported from Brewster and Pecos
counties in the Trans-Pecos and Williamson county in
central Texas. Texas persimmon is probably a minor
component of the woody vegetation in all other south-
central, south, and southwest Texas counties. It is
probably an insignificant part of vegetation north of
the tier of counties including Taylor, Callahan and
Eastland.

Most of the responses indicated that Texas per-
simmon usually inhabited rocky or stony upland soils
(Table 1). This was especially true in counties where 50
percent or more of the acreage was infested with Texas
persimmon. Such sites have potential for high produc-
tivity under proper management, which includes
brush control. Only about 20 percent of the respon-
dents felt that Texas persimmon was primarily a prob-
lem on bottomland soils. This response was especially

TABLE ‘I. OPINION OF RESPONDENTS FROM 50-COUNTY
AREA AS TO THE ASSOCIATION OF TEXAS PERSIMMON
WITH GENERAL RANGE SITES

Response)
Range site (%)
Rocky or stony, shallow soils, upland 66
Deep soils, bottomlands 21
Site not important 13

prevalent from workers near major drainageways
along such arteries as the Frio River. All the responses
in this category originated from respondents in coun-
ties where Texas persimmon is a minor problem infest-
ing 5 to 24 percent of the county's total acreage. In
counties where Texas persimmon occurred on only 1
to 4 percent of the acreage, infestations were not con-
sidered as associated with any particular range site.

About a third of the respondents observed that
Texas persimmon increased in intensity following
brush control procedures (Table 2). This is apparently
a particular problem when the associated species are
controlled by chaining, probably for two reasons.
First, many of the Texas persimmon stems bend
rather than being uprooted by the chain. Secondly,
some stems break allowing prolific root sprouting.
Root sprouting results in heavy mottes or thickets of
Texas persimmon (Figure 4).

Over 2O percent of the respondents indicated
that overgrazing, or poor management following
brush control, increased Texas persimmon infesta-
tions. Another 22 percent of the respondents felt that
Texas persimmon infestations were not associated
with management of the rangeland.

The most popular method of controlling Texas
persimmon was by basal sprays (Table 3). This is rec-
ommended by the Texas Agricultural Extension Ser-
vice, and has proven most consistent of methods
tested (Hoffman, 1972). A few ranchmen apparently
use the cut-stump method of treatment, and about 1O
percent attempt to control Texas persimmon by grub-
bing individual plants. Although a few workers at-
tempt to control Texas persimmon by rootplowing or
dozing, only limited success has been reported with
these methods. About 3O percent of the respondents
reported that Texas persimmon did not present a
problem sufficient to warrant control efforts in their
counties. All of these counties were on the periphery
of the infestation (Figure 3).

All respondents were asked to rank the impor-
tance of Texas persimmon relative to the other brush
control problems in their county. Over half of the
respondents from the most heavily infested counties
ranked Texas persimmon as their primary brush

TABLE 2. OPINIONS OF RESPONDENTSAFROM A 50-;
COUNTY AREA As TO ASSOCIATION OF MOST SEVERE
TEXAS PERSlMMON INFESTATIONS WITH PARTICULAR“

RANGE MANAGEMENT PRACTICE OR PROBLEM

Response}

Management Practice or Problem (%) 
Overgrazing ‘ "s. 22 
Any mechanical brush control method 14 
Chaining associated brush 13
Dozing associated brush 3 :1
Root-plowing associated brush 1 i
Grubbing associated brush *1
Any procedure to eliminate associated brush 4
Poor management following brush control 1
Abandonment of cropland 3
Infestations not associated with management 22
No opinion 16 -

‘a.
1r

problem. Usually, their reason for ranking Texas per-K
sirnmon first was lack of an effective and economic 
control method. Those who ranked Texas persimmon
as their second or third most important brush prob-f
lem listed "cedar" (Iuniperus spp.), honey mesquite
(Prosopis glandulosa Torr. var. glandulosa) or vario é
species of oak (Quercus spp.) as the primary proble f

However, the responses were unanimous in listin

Texas persimmon as most likely to dominate whe 

other brush species were controlled. As expected

Texas persimmon’s rank in importance as a brus

problem decreased as the acreage infested decreased;

Respondents were also asked their opinion as j

whether Texas persimmon infestations in their are
will increase in intensity, decrease or remain fairll
stable for the next 15 years (Table 4). Most respon?
dents from areas with 50 to 95 percent of their acreag
infested believed that the Texas persimmon proble;
will increase in the next 15 years. Their reasons fog
such an opinion included lack of effective an,
economical control methods, ecological adaptation 
Texas persimmon when other brush species are con;
trolled, and the ability of Texas persimmon to spreaf
into poorly managed rangeland. Some responden 

Figure 4. This motte or
clump of Texas persimmon  
developed from root sprouting
following disturbance of orig-
inal topgrowth.

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tlgi

JABLE 3. PERCENTAGE OF RESPONSES FROM 50-

    

Response

(%)

42
 2
gf-Grubbing 1 1
QEQROOTDIOWIHQ 9
§§Dozing 6

E1510 control method used . 3O

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._-
i.
5:».

iiféifiom areas of low Texas persimmon density felt that
 problem might increase, but an equal number felt
 population was and would remain relatively sta-
l-gible. Several respondents from areas of low Texas per-
 infestation also cited the value of a limited

l

gipopulation for wildlife food and cover.
 Additional information from respondents where

i
éTexas persimmon is a problem included:

 1) Until an effective, economical and dependable
I control procedure is developed, many ranchers
Ea do not wish to invest capital in attempting Texas
 persimmon control. Thus, infested ranges con-
 tinue to deteriorate and Texas persimmon con-
tinues to spread.

 2) Mechanical control methods may never prove
 successful due to the rough rocky terrain of sites
 now supporting Texas persimmon. Con-
 sequently, research should strive to develop ef-
 fective herbicides for control of this species.
Foliar sprays would be most feasible.

  3) Present chemical methods, basal sprays 0f
2,4,5-T in diesel oil, are erratic and may kill
from 50 to 100 percent of the plants. Research
is needed to develop methods with more repro-
ducible results.

é

 
  

 w  -: .77 V" ‘ w

ontrol with sprays
' Hoffman (1972) and Young et al. (1969) reported
* most consistent results from herbicide sprays oc-

rred when Texas persimmon was treated with a

 
 
  
  
  
   
   

 
  

Y-BLE 4. OPINION OF RESPONDENTS AS ro WHETHER
QEXAS PERSIMMON INFESTATIONS WILL INCREASE,
CREASE on REMAIN STABLE IN THE NEXT 15 YEARS
 THEIFR AREAS

 Percentage of opinions that Texas
. Wilder" 93199018’ persimmon infestations will —

fased on present
 eage (%) infested] Increase Decrease Not Change

  

       

70-95  s5

O 15

50-69 100 O O
25-49 67 O 33
5-25 67 1 1 22
4-5 V 35 6 59

basal spray containing 16 pounds of 2,4,5-T in 100
gallons of diesel oil. This treatment was most effective
when applied in July, August or early September.
Ranchers have reported complete control when the
Texas persimmon tops were removed at ground line
and kerosene poured on the cut stumps during Au-
gust.

Only 2 pounds per 100 gallons of herbicides in
diesel oilwater emulsion as foliar sprays and 6
pounds of herbicides per 100 gallons of diesel oil as
basal sprays were evaluated in this study. This al-
lowed a more effective separation of herbicide per-
formance. About 1.1 quarts of herbicide spray solu-
tion were required per tree for basal application of
herbicides. About 2.4 quarts of herbicide solution
were required for foliar treatment of the Texas per-
simmon plant.

A year after treatment, foliar sprays of 2,4-D,
2,4,5-T or silvex at 2 pounds per 100 gallons of solu-
tion reduced the Texas persimmon conopy by about
9O percent (Table 5). However, few plants were ‘com-
pletely controlled by the sprays. Five percent or less
of the Texas persimmon were completely defoliated
and not resprouting. Resprouts developed from
stems or roots depending on extent of damage to the
topgrowth. Where the topgrowth was killed, root
sprouts developed within 0.5 to 1 foot of the old stem
base. Results from foliar sprays of dicamba were simi-
lar to those obtained from 2,4-D and silvex. About 75
percent of the plants sprayed were completely de-
foliated, but most were resprouting from the stem
base or from roots within 0.5 feet of the stem base.
Although total canopy reduction with foliar sprays of

TABLE 5. PERCENTAGE REDUCTION OF TEXAS PER-
SIMMON CANOPIES A YEAR AFTER TREATING INDIVID-
UAL PLANTS WITH FOLIAR SPRAYS OF VARIOUS HER-
BICIDES AND HERBICIDE MIXTURES AT 2 LB/100 GAL-
LONS OF A 1:4, DIESEL OILIWATER EMULSION ON JULY
20, 1972 NEAR COMFORT, TEXAS‘

Population Overall

Treatment completely canopy
controlledz reduction

Herbicide(s) Combination (%) (%)
2,4-D — 3 a 89 cd
2,4,5-T - 2 a 94 d
Silvex — 5 a 89 cd
Picloram — 59 d 99 d
Dicamba — 9 ab 75 bc
2,4-D + picloram 2:1 42 c 99 d
2,4,5-T + picloram 1:1 4O c 99 d
Silvex + picloram 1:1 72 e 99 d
2,4-D + dicamba 1:1 18 b 99 d
2,4,5-T + dicamba 1:1 6 a 91 cd
None —- O a O a

‘Means within a column followed by the same letter are
not significantly different at the 5% level of probability.

"Completely controlled refers to 100% canopy reduction
and no signs of new sprout development.

Figure 5. Silvex + picloram (1:1) at 2 pounds per 100
gallons of diesel oil:water emulsion was the most effective
herbicide combination studied for control of Texas persim-
mon.

silvex was similar to that of 2,4-D 0r 2,4,5-T, about 5
percent of the plants completely defoliated had not
developed regrowth a year after treatment.

Picloram alone as a foliar spray reduced the
Texas persimmon canopy by 99 percent a year after
treatment (Table 5). About 60 percent of the Texas
persimmon plants were completely defoliated and
not resprouting. The combination of picloram with
silvex, 2,4,5-T or 2,4-D reduced the Texas persimmon
canopy by 99 percent a year after treatment. How-
ever, the silvex + picloram combination (1:1) was the
most successful treatment of those applied as foliar
sprays in July, 1972, relative to percentage of plants
failing to develop regrowth (Figure 5). Scifres (1972)
reported the synergistic action of silvex and picloram
as broadcast sprays for sand shinnery oak (Quercus
havardii Rydb.) control. Over 7O percent of the Texas
persimmon plants treated with silvex + picloram and
40 percent or more of the plants treated with 2,4,5-T
+ picloram or 2,4-D + picloram were completely de-
foliated and not resprouting after application of the
foliar sprays. .

Dicamba reduced the Texas persimmon canopy
by about 75 percent a year after treatment in July,
1972 (Table 5). However, only 8 percent of the plants
were completely defoliated and not resprouting. Di-

8

_2,4-D + picloram combinations which deviated i1

p substitution of one-fourth of the picloram with 2,41

   
  
   
  
  
   
   
   
   
   
    
 
 
   
  
    
  
   
 
   
   
   
  
  
   
   
   
  
  

camba + 2,4-D (1:1) tended to be slightly more effec
tive than either herbicide alone. The application o
2,4,5-T + dicamba (1:1) as a tank mix was similar if

results obtained with 2,4,5-T or dicamba alone. 
added effectiveness of 2,4,5-T and dicamba has bee 3i
noted on sand shinnery oak (Scifres, 1972), hone
mesquite (Scifres andHoffman, 1972) and Macartnei;
rose (Rose bracteata Wendl.) (Scifres, 1974) where th ‘

herbicides were applied as broadcast sprays. l)

Application of picloram or combinations l)
phenoxy herbicides with picloram in Iune 1973 wer

$-

generally more effective as foliar sprays than as bas _
treatments (Table 6). Picloram alone applied to th
foliage reduced the Texas persimmon canopy by ‘k;
percent, and 62 percent of the plants were completel 
defoliated and not resprouting after foliar treatmen A
with picloram. However, basal application of 

pounds of picloram in 100 gallons of diesel oil r;
duced the Texas persimmon canopy by only about 
percent. Less than 35 percent of the Texas persimmoi
plants were completely defoliated and not resprou g
ing a year following basal applications of picloram '   p
June, 1973. 

The foliar treatments were also less variable th ii I
the basal treatments with picloram. For instance, a .
erage percentage defoliation from foliar applicatio g .
varied i2 percent from the average whereas defoli a
tion with basal treatments varied i39 percent v.

the average. The same relationships held with

i
i

percent from the average whereas basal treatmen
varied i 39 percent.

Application of a 1:3 combination of 2,4-D + p)  
loram in Iune, 1973 was not as effective as piclor y‘
alone (Table 6). Therefore, the amount of piclor :5
applied apparently is the critical factor. Not only do

reduce the level of control but, as mentioned pre 
ously, results are more variable. However, applica
tion of the 2,4-D + picloram mixture in water + 
percent surfactant to Texas persimmon foliage did n
reduce the level of control as compared to resul
from the diesel oilzwater emulsion. Using water Q
carrier, average canopy reduction was 92 i 16 v-a
cent and 27 percent of the plants were complete
defoliated and not resprouting a year after treatmené, ‘

Results obtained from foliar applications
2,4,5—T + picloram in June 1973 were not as effectif
as those resulting from application of the same rate _ -
Iuly 1972 (Table 5). Treatment with 2,4,5-T + picl .
ram was no more effective than 2,4-D + picloram 
controlling the Texas persimmon canopy (Table 
Silvex + picloram tank mixed in a 1:1 ratio was p 3
most effective phenoxy + picloram combination y ,_
applications in June. Foliar applications of silvex 
picloram in Iune 1973 resulted in a completely 
duced Texas persimmon canopy a year after 
ment. Over 85 percent of the Texas persimmon pla  p
had not developed resprouts either from roots A,
basal stem segments the year after foliar applicati

  
 

y l 6. PERCENTAGE CANOPY REDUCTION OF TEXAS PERSIMMON A YEAR AFTER TREATING INDIVIDUAL PLANTS
 NE 1973 WITH PICLORAM AND PICLORAM + PHENOXY HERBICIDE COMBINATIONS NEAR COMFORT, TEXAS‘

  



  
  
  
  
 

Treatment Population Overall
  completely canopy
 Combination Rate Application controlledz reduction
rbicide(s) ratio (lb/100 gallons) method (%) (%)
 _ 2 Foliar 62 u 99 c
" am a — 6 Basal 34 c 54 a
a W + picloram 1.3 2 Foliar 38 c 89 bc
.  + picloram 1:3 6 Basal 14 a 38 a
g ‘-T+ picloram 1:1 2 Foliar 14 a 76 b
(T + picloram . 1:1 6 Basal 29 bc 38 a
2X + picloram 1:1 2 Foliar 88 e 100 c
§<+ picloram 1:1 s Basal a 19 ab s9 bc

 

. k‘
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i‘.
1'] vex + picloram. The application of silvex + pi-
 as a basal treatment was no more effective than
 er herbicide combinations applied in the same
H er (Table 6). Although not significantly different
 foliar applications relative to total canopy reduc-
.,- Texas persimmon, more than 8O percent of the
 i treated with the combination were resprouting
‘year after application.
i-One of the more effective herbicide basal spray
l- ents, at nearly two years after application, was
 T + picloram in a 1 to 4 combination (Table 7).
pi am combined with 2,4,5-T was generally more
I've than the application with dicamba. How-
i 2,4-D was equally effective with either picloram
 amba.
_  '> ere was little difference in the reaction of Texas
Vi» on to basal applications of silvex, picloram,
.  ex + picloram at 6 pounds per 100 gallons of
 oil relative to time of application (Table 8).
Ifsprays of silvex appeared to be slightly more
've when applied during the spring (March)
‘during the winter or summer based on average
T?» reduction. However, the percentage of the
 tion completely defoliated and not resprouting
(s... than 10 percent regardless of season of appli-
A. As in experiments discussed previously, the
{n ation of silvex and picloram was more effec-
regardless of month of treatment, than either
"de used alone at the same rate (Table 8). In-
ll» were calculated as described by Scifres
Regardless of the month of treatment, the sil-
‘icloram was synergistic for Texas persimmon
 Also, the combination of silvex + picloram
 noticeably affected by season of application.
trast to studies with other herbicides, the her-
zzcombination appeared to be slightly more ef-
Tduring the cooler months than during the

F l with Pelleted Herbicides
 (1972) reported excellent results from
lication ofabout 1 gram of active picloram as

 s within a column followed by the same letter are not significantly different at the 5% level of probability.
 pletely controlled refers to 100% canopy reduction and no signs of new sprout development.

10 percent pellets for every centimeter ofstem diame-
ter of Texas persimmon? The most effective date of
application was October. This treatment resulted in
96 percent control of Texas persimmon at a year after
treatment with no damage to desirable sod grasses. In
our studies, picloram pellets were applied based on
amount of active ingredient per foot of canopy diame-
ter. The Texas persimmon plants have canopy
diameters ranging from 2 to 15 feet. Average canopy
diameter was 7.5 feet based on 71 trees measured in
the plots treated with the pellets.

. Averaged across application dates of November,
March, and June, there was no difference in canopy
reduction of Texas persimmon by the picloram pellets
(Table 9). Applying 0.005 ounce per foot of canopy

3R0ughly equivalent t0 0.1 ounce per inch of stem diameter.

TABLE 7. PERCENTAGE REDUCTION OF TEXAS PERSIM-

l MON 23 MONTHS AFTER TREATING INDIVIDUAL PLANTS

WITH BASAL SPRAYS OF VARIOUS HERBICIDES AND
HERBICIDE MIXTURES AT 6 LB/100 GALLONS OF DIESEL
OIL ON JULY 20, 1972 NEAR COMFORT, TEXAS‘

Treatment Population Overall
completely canopy
Combination controlledf‘ reduction
Herbicide(s) ratio (%) (%)
2,4-D — 5 a 76 c
2,4,5-T — 5 a 79 cd
Dicamba — 6 a 57 b
2,4-D + picloram 21 14 b 91 de
2,4,5-T + picloram 1.1 32 c 82 cde
2,4,5-T + picloram 1:4 46 d 96 e
2,4-D + dicamba 1 1 22 bc 8O cd
2,4,5-T + dicamba 1 1 6 a 38 a
None — O a 38 a

‘Means within a column followed by the same letter are
not significantly different at the 5% level of probability.

zCompletely controlled refers to 100% canopy reduction
and no sprout development.

;.f ‘*9 .
’ is -» 

Figure 6. Application of 0.02 ounce of picloram pellets per
foot of canopy diameter t0 the base of the plants resulted in
excellent control. of Texas persimmon.

diameter was less effective than 0.011 0r 0.022
ounces. Most consistent results occurred when at
least 0.022 ounces of picloram pellets were applied
per foot of canopy diameter (Figure 6). Based on an
average tree size of 7.5 feet canopy diameter, about
0.165 ounces active ingredient (1.65 ounces of the 10
percent pellets) were required per tree. One pound of
the active ingredient would treat nearly 100 of the
average size trees. Application of picloram pellets in
March, just before spring rains, controlled more
Texas persimmon than November or ]une applica-
tions (Table 9). Only in March was the 0.044 ounce of
picloram pellets per foot of canopy diameter
evaluated. This treatment completely controlled the
Texas persimmon. Canopies were completely reduced
at a year after treatment and no resprouts were found
on the plants.

Where 0.022 ounce per foot of canopy diameter
of picloram was applied to the average size Texas
persimmon, grasses were completely controlled
within a 2-foot radius of the base of the treated plant
(Figure 7). A year was usually required for grass re-
covery where the high rate was applied. Where 0.044
ounce per foot of canopy diameter was applied, grass
as far as 15 feet downslope in strips 3 feet wide was
completely controlled.

10

   

 
  
  
  
 
 
 
  
   
    
 
  
  
 
 
   
 
    
   
  
   
   
 
  
    
  
   
    
   

TABLE 8. PERCENTAGE CANOPY REDUCTION OF TEXAS
PERSIMMON AND PERCENTAGE POPULATION COM
PLETELY CONTROLLED WHEN CHECKED IN JUNE 197 »
(A YEAR OR MORE AFTER APPLICATION). SEPARAT
SETS OF PLOTS WERE TREATED ON THREE DATES WIT 
BASAL APPLICATION (6 LB/100 GALLONS OF DIESE
OIL) OF SILVEX, PICLORAM AND THEIR COMBINATIO .
IN 1:1 RATIO IN 1972 AND 1973 NEAR COMFORT, TEXAS?

Month of Treatment‘

.‘

 

Herbicides November March Junefl;
Overall canopy reduction ("/>§n

Silvex 4o a s9 b 42 a ;
Picloram 67 b — 54 abi
Silvex + picloram 97 c 93 c 89 c
Population completely controlled

Silvex 4 a 4 o e df
Picloram 37 f _ 17 e a
Silvex + picloram 7O h I 58 gh 49 lg;

‘Means followed by the same letter are not significantly r
different at the 5% level. p;
zCompletely controlled refers to 100% canopy reducti I
and no sprout development. 

Karbutilate pellets were evaluated in only f]
experiment, conducted in March 1973. Herbicid
symptoms developed more slowly with karbutilat
than with picloram. The foliage characteristically bij
came chlorotic before leaf drop. The 0.005 ounce  .
karbutilate per foot of canopy diameter did not aff- 
the Texas persimmon plants based on evaluation f
months after treatment. Where 0.011 ounce of 
butilate per foot of canopy diameter was appliei
canopy reduction averaged 62 percent and 13 perce fl
of the plants were completely controlled. Where 0.0 l.
ounce per foot of canopy diameter was applied, v 
foliation averaged 95 percent and about 70 percent 
the plants were completely controlled. Therefore, 
higher rates of karbutilate were roughly equivalent 4.
picloram for Texas persimmon control. 

DISCUSSION

Texas persimmon control is usually erratic ev’
with high application rates of 2,4,5-T as an individ 
plant treatment. Therefore, three variables were co i. -
sidered in evaluating herbicide performance in _i
study; average canopy reduction, variation in cano ‘
reduction within a treatment, and percentage of it; i
population completely controlled.  A

The phenoxy herbicides, 2,4-D, 2,4,5-T and  .
vex reduced Texas persimmon canopies from 75 to ‘a
percent. However, in no case were more than 10 
cent of the plants completely controlled. This I  i
curred, presumably, due to the high rates of pheno 
herbicides required for Texas persimmon control. I

f

 

Figure 7. Although picloram
pellets were excellent for con-
trol of Texas persimmon,
grass damage was evident fora
year after their application.

gcamba, alone 0r combined with 2,4-D 0r 2,4,5-T, also
ireduced the Texas persimmon canopies but rarely con-
itrolled over 2O percent of the population. Invariably,
 applications of these herbicides were less effec-
five than foliar treatments.
If To evaluate the performance of herbicide combi-
 tions, the method of calculating expected perfor-
Elaance of the combination based on performance of
e individual components as outlined by Scifres
1972) was employed. Results from application of fo-
in sprays, whether considering level of canopy
ygéiieduction or percentage of plants completely con-
implied, indicated that 2,4-D + picloram, 2,4,5-T
picloram, 2,4-D + dicamba or 2,4,5-T + dicamba
mbinations were ”additive.” Additivity indicates
 at performance of the herbicides in mixtures could
 anticipated by control level resulting from use of
fther component alone at the same application rate.
‘ynergism results when the combination of her-
g' 'des controls more plants than would be expected
pased on performance of the herbicides applied
‘fine. In considering canopy reduction, the silvex +
“icloram combination was usually additive. How-
I er, based on percentage of plants completely con-
Ygllled, results from the combination were synergistic.
v ' reaction occurred regardless of season or year of
gipplication. Also, the relatively low rates of the com-
 tion in this study resulted in good levels of Texas
irsirryiinon control.
 That picloram and combinations containing pi-
 am were more effective as foliar than as basal
“Trays is difficult to explain in view of the perform-
 of the pellets. Picloram is usually readily taken
by the roots of many species of woody plants as
“enced by control levels resulting from pellet ap-
 tions. Therefore, it was expected that basal ap-
fation, which applied 1.5 times more picloram to
if.“ plant, would be more effective than foliar treat-

     
    

Picloram pellets were equal to silvex + picloram
sprays for Texas persimmon control. Pellets offer
some advantage in application of herbicides in remote
areas although high rates of the pellets should not be
applied to steep slopes.

TABLE 9. PERCENTAGE CANOPY REDUCTION OF TEXAS
PERSIMMON AND PERCENTAGE POPULATION COM-
PLETELY CONTROLLED WHEN CHECKED IN JUNE 1974
(A YEAR OR MORE AFTER APPLICATION). SEPARATE
SETS OF PLOTS WERE TREATED ON THREE DATES WITH
VARIOUS RATES OF PICLORAM PELLETS IN 1972 AND
1973 NEAR COMFORT, TEXAS‘

Month of treatment
Application rate

(oz/ft can diam) November March June Avg.

Overall canopy reduction (%)

0.005 69 a 81 abc 72 a 74 r

0.011 78 ab 96 de 84 bc 86 s

0.022 95 de 99 e 87 cd 94 s
Date avg. 81 x 92 x 81 x

Population completely controlled (%)2

0.005 10f 19f 21 f 17 o

0.011 46 gh 55 h 85 g 45 p

0.022 75 i 89 j 48 h 71 q
Date avg. 44 lm 541m 35 l

‘Means followed by the same letter are not significantly
different at the 5% level. Within an evaluation category,
rate x date‘ means, rate or date averages can be compared.

zComplete control refers to 100% canopy reduction and
no signs of sprout development.

11

The more effective individual plant treatments
described in this study should have promise for con-
trol of light infestations of Texas persimmon or as

follow up to broadcast methods where Texas per- p

LITERATURE CITED 

Hoffman, Garlyn O. 1972. Texas persimmon. A pesky
range problem. Texas Agr. Prog. 18:(1)8-9.

Meyer, R. E. 1974. Morphology and anatomy of Texas per-
simmon (Diospyros texana Scheele.). Texas Agr. Exp.
Sta. Bull. 1147.

Scifres, C. I. 1972. Herbicide interactions in control of sand
shinnery oak. I. Range Manage. 25:386-389.

Scifres, C. I. 1974. Fall application of herbicides improves
Macartney rose-infested Coastal Prairie rangeland. I.
Range Manage. 27:(In press).

Scifres, C. I. and G. O. Hoffman. 1972. Comparative sus-

ACKNOWLEDGMENTS

Cooperation of Mr. Casper Real, Real Ranch,
Comfort, Texas in furnishing land and assistance for

this research is greatly appreciated. Mr. G. O.

Hoffman, Extension Brush and Weed Control
Specialist, cooperated in the problem survey. Her-

All programs and information of The Texas Agricultural Experiment Station are available to everyone without regard to r;

color, religion, sex, age, or national origin.

The Texas Agricultural Experiment Station

Texas A8cM University

College Station, Texas 77843

j. E. Miller, Director
Publication

‘Penalty For Private Use, $300

Third __
Class

1M—10-75

 

    
 
  
   
     
 
   
 
  

simmon is a component of mixed brush. Also, 
are many areas, especially in the Edwards 
where broadcast methods are not feasible due to t
terrain. 

é
a

ceptibility of honey mesquite to dicamba and 2,4,5‘
I. Range Manage. 25:143-145i'~ 

Vines, R. A. 1960. Trees, Shrubs and Woody Vines of 

Southwest. Univ. of Texas Press, Austin. 1104 pp. f,
Wilson, Bobby V. 1969. Annual carbohydrate storage of S“
Texas persimmon (Diospyros texana). MA The i
Southwest Texas Univ., San Marcos. 19 pp.  
Young, Leroy I., Bobby Wilson, Iames Tabler, and 
Ellis. 1969. A study of the ecology and control of _
Texas Persimmon (Diospyros texana). Prog. Re“
Southwest Texas Univ., San Marcos. 19 pp. ‘

bicides for the study were furnished by AmCh
Co., Velsicol Chemical Co., The Dow Chemical 
and FMC Corp. I. L. Mutz and H. G. McCall aide
plot installation and evaluation. 

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