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i ED CONTROL
SEARCH

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D OKLAHOMA
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i, AGRICULTURAL EXPERIMENT STATION /J. E. Miller, Director / Texas A&M University / College Station, Texas

Cover photo

   
  
  
 
   
  
  

Pigweed (carelessweed) competes with guar grown wit,
quate chemical and cultural control methods-wrap w
pod production are decreased, and harvesting losses are g f

Acknowledgments

Appreciation is expressed to Roy StaffoT
Department of Agriculture, at the Texas *
versity Agricultural Research and Extensiom
at Vernon, and Dwane Scott, farm demo
Texas Agricultural Extension Service, Welli
their assistance in providing seed and advi g
tural practices in conducting field invesi,
Appreciation is also expressed to James M,
chemist with Celanese Corp. (formerly Stein,
Company), Vernon, Texas, for conducting '
and protein analyses. Photograph was pro
Roy Stafford. 

Contents

Summary ..............................  ________________________________________ __ 4
Introduction __________________________________________________________________ __ 5
Materials and Methods _______________________________________________ __ 6
Preplant Treatments ............................................. _- 6
Perkins, Oklahoma ........................................... ._ 6
Wellington, Texas .................  ........................ -. 6
Lubbock, Texas ............................................... .. 6
Preemergence Treatments ......  ............................ -- 6
Perkins, Oklahoma ........................................... .. 6
Lubbock, Texas ............................................... .. 6
Brownfield, Texas ........................................... .. 6
Postemergence Treatments ................................... .. 6
Results and Discussion ............................................... .. 7
Preplant Treatments ............................................. .. 7
Perkins, Oklahoma ........................................... -- 7
Wellington and Lubbock, Texas ................ .- 7
Preemergence Treatments ..................................... .. 8
Perkins, Oklahoma ........................................... .. 8
Lubbock, Texas ............................................... .. 8
Brownfield, Texas ........................................... -- 8
Postemergence Treatments ................................... .. 9
Guar Quality ........................................................... .. 10
Literature Cited ........................................................... .. 10
Appendix I ................................................................... .. ll

3

  
   
    
  
   
   
  
   
   
    
   
   
  
 
 
   
 

Summary

To improve weed control technology .3“
stimulate interest in obtaining herbicide label
guar, preplant incorporated, preemergence and
emergence applications of herbicides were 
Western Oklahoma and the Panhandle area of e-
from 1961 to 1972. Soil types varied from 1
sand.

Dinitroanaline herbicides including trifl
(Treflan), nitralin (Planavin), dinitramine f?
and CGA 10832 (Tolban), applied prior to p =3
and incorporated with a tandem disk, safely w;
weeds in the crop when seed were planted in‘?
soil. Plantings in cold soil after application
fluralin resulted in injury to the crop in 0 H
DCPA (Dacthal) and EPTC (Eptam) were very;
tive against weeds in Oklahoma tests but f;
give consistent results in Texas. i“

Herbicides applied preemergence at 
that controlled pigweed, sandbur or crabgrass 
injuring the crop were DCPA, linuron ( 
chloramben (Amiben), alachlor (Lasso), diph
(Dymid or Enid), nitralin and diuron (Karmj

Many herbicides were evaluated for 
gence use. Only MSMA and bentazone (B_
appear to have promise for this purpose in g 

Herbicides did not affect gum content org
percent of guar seed regardless of whether pla I‘
injured or not. ~ ‘"-

CAUTION: The only herbicide labeled for use infl
trifluralin (Treflan) which is to be incorporated 
planting. Although other herbicides named in this _
appear to be safe on guar, they should not be so 

registration is specifically granted by state or federal a _-'_~

  

  
  
   
    
   
  
 
 
   
   
  
   
    
  
   
   
   
    
   

 ~ crops are of vital interest as alternatives in
"fr. supplemental income, production on divert-
 and stimulation of new jobs and industries.
“j amopsis tetragonoloba (L.) Taub.] is a warm-
egume that produces galactomannan gum.
pm is a binding agent with many industrial
stuff uses. Although guar is grown primarily
sale, yields of cotton and other crops have
i’ eased when grown in rotation with guar.
lds‘ of diyland cotton have been increased
ds per acre due to rotation with guar, com-
 continuous cotton production. This advan-
bably is a result of nitrogen fixation by the
 us crop (6).

i‘ was probably first introduced into the
igStates in 1903 as a U.S. Department of Agri-
fplant induction from India (4). Since then,
‘ has been evaluated in several areas and found
 suited for the Southwest due to the soils,
wing season, high temperatures and its drouth-
f characteristics.

nsive research in guar improvement, diseases,
ifpractices and genetics have been conducted
  Research in Oklahoma and other areas
 summarized (4). Presently guar production
g" trated primarily in the Rolling Plains area
t" western Oklahoma and West Texas where
"ial processing facilities for guar are located.
"ely, assistant direéior, The Texas Agricultural Experi-
dtion, former associate professor; professor, The Texas

iural Experiment Station, Bushland; and professor, The
 Agricultural Experiment Station, Stillwater.

of a trademark or a proprietary product does not
 a guarantee or warranty of the product by The
f": 'cultural Experiment Station or The Oklahoma Agri-
 periment Station and does not imply its approval to
ion of other products that also may be suitable.

i.

. Weed Control Research in Guar
in Texas and Oklahoma

1961-72

D. T. Smith, A. F. Wiese and P. W. Scmtelmunn*

Guar acreage in the Texas-Oklahoma region in 1971
was estimated a.t 200,000 acres.

Successful production of any crop is highly de-
pendent on economical control of other unwanted
vegetation. Thus, commercial acceptance and pro-
duction of guar depends on the reliability and cost
of eliminating weed competition. Som.e of the first
herbicide studies in guar were conducted by Elder,
Matlock and Santelmann (2, 3) who found that nap-
talam (Alanap) and EPTC (Eptam) were safe on
guar. McMurphy (5) showed that 2,4-DB (Butyrac or
Butoxone) at 2 pounds per acre could be used as a
postemergence treatment on guar. However, none
of these chemicals have been registered for commercial
use on guar due to the relatively small acreage in
relation to costs and difficulties in obtaining a fed-
erally approved label.

Since 1965, guar acreage has expanded rapidly,
increasing the potential market for herbicides. How-
ever trifluralin (Treflan), which was for preplant
incorporation, is the only labeled herbicide for the
crop. Some general observations and techniques for
control of weeds in guar were summarized in relation-
ship to common cultural and production practices for
the crop (7). Frequently, guar is planted flat or
furrow-planted, and the crop is cultivated to control
weeds. However, low-set seed pods are difficult to
harvest since soil that is ridged up in the row during
cultivation hampers combining and increases harvest
losses. Covering branches with soil during cultivation
tends to promote southern leaf blight.

The objective of this research was to develop safe,
effective herb-icides for weed control that would help
minimize production costs in guar. Weed research,
conducted over a 12-year period at several locations
in Texas and Oklahoma, is presented to summarize

5

data for ‘the guar industry and to stimulate interest
in obtaining labels for herbicides for commercial use
in guar.

MATERIALS AND METHODS

Preplant Treatments

Perkins, Oklahoma

Trifluralin (Treflan), DCPA (Dacthal) and EPTC
(Eptam) (see Appendix 1 for a complete description)
were investigated for weed control and guar tolerance
for 4 years on Norge loam between 1961 and 1966.
Chemicals were incorporated with a garden rototille-r,
and Groehler-Z or Brooks guar was planted. Plots
were two rows by 25 feet or larger with three repli-
cations, and herbicides were applied in 30 gallons
of water per acre. The plot area was infested with
pigweed (carelessweed or Amaranthus hybridus L. or
A. albus) or smooth crabgrass [Digitaria ischaemum
(Schreb.) Muhl.].

Wellington, Texas

Preplant herbicide treatments were investigated
in 1967 and 1969 on Amarillo fine sandy loam. Herb-i-
cides were applied in 40 gallons of water per acre,
and plots were four rows by 30 or 35 feet with three
replications. Trifluralin, nitralin (Planavin) and
DCPA were incorporated twice with a tandem disk
before soil was listed into beds. In 1967 chemicals
were applied April 17, and Hall guar was planted
the same day. Rainfall amounted to 0.8 inch within
l7 days after planting. In 1969 treatments were
applied May 23, and Hall gua.r was planted June 9.
Rainfall totaled 2.5 inches within 11 days after plant-
ing. Injury to guar and control of pigweed were
visually estimated in early July in both trials. Yields
were obtained in 1969.

Lubbock, Texas

Preplant trials were conducted in 1971 and 1972
on Amarillo loam. Plots were four rows by 35 feet
with three replications of treatments. Herbicides were
applied in 15 gallons of water per acre with a tractor-
mounted plot sprayer and were immediately incorpo-
rated twice with a tandem disk before soil was listed
into beds. In 1971 trifluralin, nitralin and DCPA
were applied in late April, and Brooks guar was
planted in early June. Pigweed control, guar injury
and seed yield of guar were evaluated.

In 1972 trifluralin, nitralin, dinitramine (Cobex)
and CGA-10832 (Tolban) were applied in mid to late
March in two experiments. Chemicals were incor-
porated twice with a tandem disk, and soil was bedded
in mid to late March. Brooks guar was planted in

6

‘ arol), dipropetryn (Sancap), terbutryn (Igran

  
  
  
 
 
 
    
     

mid July to evaluate crop tolerance. Only guar i‘
and stand were reco-rded since weeds were not p l
in plots. Since seed yields were low, fresh wei "
guar plants were obtained to evaluate herbicide

Preemergence Tnleatments

Perkins, Oklahoma

Preemergence weed control experiments in.
were conducted from 1961 to 1966 with the
conditions as previously described for preplant 
Preemergence treatments were applied within
after planting. In all instances, 0.7 to 1.0 ii
rainfall occurred within 3 to 10 days after pl‘:
except in 1966. In 1966, 1.1 inches of "
occurred 1 month after planting. Injury _
and control of pigweed and smooth crabgra”
visually estimated 3 to 4 weeks after plantingfli
yields of guar were obtained in 1961, 1962 - ii
by hand harvesting plants and mechanically 
ing seed. 

   
  
 
  
   
  
  
   
 
    
  
  
  
 
 
 
     
 
 
  
   

l‘.
.. ‘

Lubbock, Texas i

Two preemergence trials were conducted f‘? ‘
in 1971. Herbicides investigated were mf
alachlor (Lasso), diuron (Karmex), prometry <-

tryne (Evik) and cyanazine (Bladex). In ex a.
Brooks guar was planted in early June, a 
cides were sprayed the following day. Rai _'
0.4 inch within 4 days after planting. In expe!
herbicides were applied in late May, but 
be replanted 20 days later due to soil crusti 1
damage and light hail. Total rainfall was 2.‘
within 10 days after herbicide application. j 
were four rows by 35 feet with three rep 
Pigweed control and guar injury were visu Q
mated 4 weeks after planting, and plots 
harvested and threshed to determine seed A

Brownfield, Texas

In 1971 Brooks guar was furrow-pl 
Brownfield sand in late May but was repl _ l;
minimum soil disturbance, ll days later af i
sand damage. In l972Brooks guar was 
late May, and herbicides were applied the 
In both years 0.5 inch or more rainfall oc , 
in 2 days after application. Sandbur (Cenc ‘
and pigweed control were evaluated in 1971 
respectively. Guar stand was determined n If
and yields were obtained in 1972. I

Postemergence Treatments _
Tolerance of guar to postemergence 
treatments was evaluated in two experimen,

  

 

Yield (lb/acre)
Rate No. of years Pigweed Crabgrass Guar
(lb/acre) evaluated control ("/,,) control 1%) in|'ury (°/.,) 1962 1963
15 18 O 210 560
0.75 4 9O 98 22 480
1.5 4 90 95 18 400
4.0 4 88 67 5 280 480

   
  
   
  
 
  
  
   
   
    
  
   
   
 
   
  
  

iriments were conducted between 1961 and 196
- were not statistically analyzed for this table.

1 k, Texas, in 1971. In one experiment,
 was planted June 8, and herbicides were
£1 month later when guar was 4 to 6 inches tall
 "0 was l inch tall. In a second experiment,
guar was planted June 24 and was treated
 ~ later when the weed~free guar crop was
“ tall. Plots were four rows by 35 feet with
 lications. Treatments included MSMA,
‘Ynil (Brom.inal or Buctril), bentazone (Basa-
 oroxuron (Tenoran or N orex), prometryne
xone (Probe). Chemicals were sprayed over
goof the crop in 15 gallons of water per acre
 0.5-percent surfactant. Guar injury was

' timated 3 weeks after treatment, and yields
tained by hand harvesting 20 or more feet
"h mid-October.

il

p ibited postemergence selectivity on guar the
year. Brooks guar was planted in late May
 loam. MSMA, b-romoxyn.il, bentazone and
_ ron were applied over the top of guar at

tes (June 21, July 26 and August 9) to evaluate
prance in relation to crop size and develop~
uar injury was visually estimated 5 days after
, _ lication date, and yields were obtained in
 taber. Plots were two rows by 20 feet with
' lications.

    

Pigweed control (7,)

}E»l- 'al was conducted in 1972 based on chemicals 1

6,- however, since all of the above treatments were not included in the same experi-

RESULTS AND DISCUSSION
Preplant Treatments

Perkins, Oklahoma

Trifluralin at 0.75 or 1.5 pounds per acre gave
90-percent control of pigweed and 95- to 98-percent
control of crabgrass (Table 1). Weed control with
EPTC was not as consistent as with trifluralin. In
1963 guar yields tended to be lower where either
herbicide was applied.

Wellington and Lubbock, Texas

Trifluralin and nitralin were highly effective in
controlling pigweed on two soil types, although some
pigweed was not controlled at 0.5 pound per acre on
fine sandy loam in 1967 (Table 2). Pigweed control
with DCPA, EPTC or vernolate (Vernam) was not as
high or consistent as with trifluralin or nitralin except
in 1969 when all treatments were effective.

Guar seedlings were visib-ly injured by trifluralin
on fine sandy lo-am and loam; however, yields tended
to be lower only where the high rate of trifluralin was
applied on loam (Table 2). EPTC or vernolate
injured guar, but yields were not affected later.
There was no indication that nitralin or DCPA
affected guar.

 PIGWEED CONTRQL AND GUAR RESPONSE TO PREPLANT HERBICIDE TREATMENTS ON FINE SANDY LOAM AND LOAM SOIL IN TEXAS‘

 

  

Guar iniury 1%)’ ‘Yield (lb./acre)
_‘_' Rate Fme sandy loom -—L-oim—- Fine sandy Fine sandy
(Aide (lb/acre) 1967 1969 1971 loam, 1969 Loam loam, 1969 Loam
 control 0° 0" 0" 0° 3" 910“ 420"
’ 0.5 78"‘ 100' 100' 43“ 33" 735'“ 800'
1.0 93' 100' 97' 87' 87' 1000'” 240“
0.5 87"’ 98' 100' 3' 17' 1020' 700'
1.0 l; 93' 97' 100' 3° 13" 972'“ 802'
6.0 ‘t 671D 96a 0c 8801b
10.0 78"’ 100' 87' 3° 17" 710" 800'
4.0 10° 100' 27”" 980'”
A‘ 4.0 49'" 98' 37” 870'"

   
 
 

“ was observed on guar in 1967 on fine sandy loam.

1 l‘
x
‘Y:

fy loam soil was at Wellington, and loam soil was at Lubbock.

Means with the same letter are not different (P<0.05).

lavas applied at 0.75 and 1.5 pounds per acre on loam at Lubbock.

Since so-me guar injury was observed from tri-
fluralin, additional experiments were conducted in
1972 “in which high rates of similar herbicides were
applied, and guar was planted after soil was wann
(data not shown). When trifluralin was applied at
0.5, 1.0 and 2.0 (four times the recommended rate)
pounds per acre, there was no indication of injury
to guar seedlings, and crop stand was not affected.
Similar safety and guar tolerance were observed with
nitralin at 1.5, dinitramine at 1.0 or CGA-10832 at
1.0 pounds per acre, all of which are similar to tri-
fluralin in chemical structure, soil activity and mode
of action. Consequently, where these herbicides
(dinitroaniline chemicals) are disk incorporated, guar
growth is comparable to or greater than in untreated
controls when the crop is planted at the proper time
in warm soil. This safety may be lacking when seed
is planted in cool or "wet soil, and chemicals tend to
increase the usual stresses on seedlings as they emerge.

Preemergence Treatments

Perkins, Oklahoma

Control of pigweed and crabgrass with pre-
emergence herbicides in Oklahoma was excellent with
DCPA, linuron (Lorox), chloramben (Amibem) at
4 pounds per acre and diphenam.id (Dymid or Enide)
(Table 3). All of these treatments were evaluated
for 2 to 5 years and consistently gave good to excellent
weed control each year. Slight guar injury occurred
from linuron at 2 pounds per acre or diphenamid, and
in l out of 2 years yields tended to be lower than in
untreated controls. Chloramben at 4 pounds per acre
gave significant injury to guar, but yield was only
slightly affected 1 out of 4 years. Although chlor-
propham (Chloro IPC) or propachlor (Ramrod) were
safe to use on guar, b-roadleaf and grass control was
generally less than 80 percent under the warm dry
conditions in southwestern Oklaho-ma.

Lubbock, Texas

In trials on loam soil, preemergence treatments
were applied after guar was planted in one experi-

TABLE 3. WEEDICONTROL AND GUAR TOLERANCE TO PREEMERGENCE HERBICIDE TREATMENTS ON LOAM NEAR PERKINS, OKLAH

   
 
 
  
 
 
 
  
 
 
 
  
 
 
  
 
 
  
 
  
 
 
  
 
  
  
 
 
  
 
 
 
  
  
 
 
 

ment, and in another experiment guar was replan A
20 days after the initial herbicide application (TableT
Trifluralin, which is usually disk incorporated, i.
90-percent pigweed control when applied at 1 p0 l‘
per acre. However, the herbicide was not eff - 
at lower rates or when guar was replanted. Altho 
slight crop injury was observed;- preemergence app
cation of trifluralin tended to enhance yields. a
chlor at 1 pound per acre gave 97-percent pi f‘
control, but weeds were not controlled where 
was replanted in alachlor-treated soil. Guar tole j g
to alachlor was excellent, and yields were not aff
in these trials. However, severe guar injury occut
in trials near Vernon, Texas, in 197 3 (I. R. Mul?
unpublished data), indicating that crop injury
occur under some conditions. Pigweed control 2;
diuron was good to excellent, but the herbicide?
not effective after replanting. Yields tended to?
higher where diuron was applied, compared to ii
treated controls. ‘

_ Several s-triazine herbicides (prometryne, dip 
tryn, terbutryn, ametryne and cyanazine) consis 
controlled pigweed and were still effective at .-‘
higher rates when guar was replanted. However, s,
stand was reduced and / or seedlings were disco 
from these s-triazines that have shown toleran
several other agronomic crops. In all instances, 
were reduced in either the initial or replanted s):
"further indicating the lack of guar tolerance to‘
herbicide group. SAN-9789 (Zorial), a new h "
being developed for cotton, was effective on pi»,
in the initial planting, but not when guar 
planted. Guar exhibited excellent tolerance to f
9789—yields were not affected in either the init l
replanted stands. 

Brownfield, Texas ,

Preemergence herbicide treatments are 
tently more phytotoxic on sandy soils than on i}
soil types with higher clay and organic mat - i
tents. Consequently, preemergence herbicides;
evaluated for 2 years on a Brownfield sand (T A

  

Rate No. of years Pigweed Crabgrass Guar Yield “bl/d '

Herbicide (lb/acre) evaluated control l%l con-trol (70) injury (7.) 1962

Untreated control l5 ‘l8 0 210'

DCPA 8 3 96 93 3 405‘

Linuron - l 2 90 80 0 340"

2 2 95 95 l0 300"

Chloramben 2 5 76 80 8 270'

4 4 95 87 22 370'

Diphenamid 6 5 94 92 8 350'
Chlorpropham 4 3 76 80 3
Propachlor 5 3 80 86 6

 

‘Several experiments were conducted between 1961 and i966; however, since all treatments were not included in the same experi 
on weed control and guar iniury were not statistically analyzed. Means of guar yields, followed by the same letter, are not signif’

ferent (P<0.‘05).

8

 
 
  

  
   
   
   
   
  
  
  
  
  
   
  
  
  
 
   
   
   

 
  

‘GUAR INJURY AND STAND AND PIGWEED CONTROL AFTER PREEMERGENCE HERBICIDE APPLICATIONS ON LOAM NEAR LUBBOCK, TEXAS,

R fe Pigweed control (%) Guar iniury (%) Yield (lb/acre)
O
(lb./acre) Experiment 1 Experiment 2 Experiment 1 Experiment 2 Experiment 1 Experiment 2
0: 0°‘! 7“d 0“d 570' 520':
0.5 77 ° 43° 10° 7° 535' 720'
1.0 90'” 57”° 17°“ 13°“ 790' 320'
1.0 97' 0° 0“ 7°“ 530' 340'
2.0 100' 53° 7“ 20”°“ 300' 540”°“
0.5 73°b 0°d 3“d 0“d 330' 700'”
1.0 37' ° 30° 20° 3° 750' 790'
1.0 a 100' 53”° 33°“ 27°“ 500'” 450°“
2.0 100' 93' 30' 37' 100“ 220°‘
1.5 97' 43°“ 7“ 37”°“ 540'” . 770'”
3.0 100' 33'” 33”° 50'” 320”°“ 450°“
1.5 97' 50”° 23°“ 47'”° 290°“ 590'”°
1.0 100' 53”° 53” 53'” 330'°“ 410“°
1.0 93' 37°“ 27° 17°“ 730' 550'”°
2.0 100' 37'” 37' 33”°“ 540' 130°
1.0 90'” 33°“ o“ 0“ 530' 710'”

“ letter are not different (P<0.05).

e treatments completely eliminated pigweed.
'3 where guar was replanted in 1971, only
‘__‘_".~ and dipropetryn gave 70 percent or more
10f sandbur. In both 1971 and 1972 guar
A excellent tolerance t0 alachlor and nitralin
 commonly used in other crops on this soil
Seedling stands and seed yields were compar-

jhen application rates of alachlor and nitralin
, bled.

 lack of guar tolerance to preemergence appli-
fof s-triazine herbicides observed on 10am soil
‘i, irmed in these trials. Dipropetryn, prome-
‘t a terbutryn severely reduced the stand when
 replanted in 1971 or after preemergence
t in 1972.

9.. WEED CONTROL AND GUAR RESPONSE FROM PREEMER-
Q! RBICIDES ON SAND IN 1971 AND 1972 NEAR BROWNFIELD,

Weed control (%) Guar stand Yield

 

 

g Rot SQ db P_ d (No./10 ft) (lb./acre)
 e n ur rgwee
 (lb/acre) (19711 (1972) 1971 1972 1972
 control 33'” 0” 35' 22' 1020'”
., 1.0 50;” 100' 29' 13': 1030;”
2.0 10 100' 34' 15' 570 °
0.5 100' 19' 1420'
1.0 70"’ 100' 20'” 15'” 500”°
. ' ' 3° 20'
i3’ 38'”, . lgg 4° 4"
3.0 33'; 100' 0° 1°
1.0 47'” 100' 13" 1°
1.0’ 47'” 100' 4° 7”°

_ were applied in late May. In 1971 guar was replanted
" later. Rainfall (0.5 inch or more) occurred within 2 days
,tment both years. Means followed by the same letter are
Q. t (P<0.05).

at1.5 lb./acre in 1971.

=51 1.5 lb./acre in 1971.

lthose of untreated controls but tended to be .

Ament 1 guar was planted and treated June 8, and 0.4 inch of rainfall occurred within 1O days. In Experiment 2 herbicides were
Jflay 19; the original stand was damaged by hail, and after 2.8 inches of rainfall, guar was replanted 20 days later. Means with

Postemergence Treatments

Several herbicides that had exhibited selectivity
in other broadleaf crops were evaluated on guar in
two experiments at Lubbock, Texas, in 1971 (Table
6). Pigweed control was 70 percent or higher with
MSMA at 4 pounds per acre and with prometryne
and methoxone, each at 1 pound per acre. However,
crop tolerance was the primary objective of the experi-
ment. Visual injury to guar from MSMA was higher
when larger guar was treated, but yield reductions
appeared to be higher when smaller guar was treated.
Guar tolerance to bromoxynil and bentazone was
excellent, and yields were not adversely affected by
either herbicide. Chloroxuron has effectively con-
trolled weeds in soybeans, another legume crop. How-
ever, in one experiment, chloroxuron damage to guar
was about equal to the degree of pigweed control.
Prometryne and methoxone gave good to excellent
pigweed control, but 6-inch guar was severely injured
and yields were reduced.

In 1972 MSMA, bromoxynil, bentazone and chlor-
oxuron were sprayed over the top of guar at three
dates to evaluate crop tolerance at different growth
stages (Table 7). Five d.ays after guar in the cotyledon
stage was sprayed, crop tolerance was good to excel-
lent. But 3 weeks later, guar injury was severe (30 to
70 percent) in all plots except‘ where MSMA or benta-
zone were applied. When the sam.e treatments were
applied in late July when guar had 7 to l0 leaves or
in early August when pods were filling, injury to guar
was more severe than when treated at the cotyledon
stage. Only MSMA at 2 pounds per acre gave less
than ZO-percent injury at all application dates. All
treatments at all application dates reduced yields
except MSMA at 2 pounds per acre at the 7- to IO-leaf
stage and bentazone at 1 pound per acre at the 7- to
10-leaf or pod-filling stages.

1+
\

   
     
  
  
  
   
  
  
  
   
  
  
   
  
   
  
    
  

TABLE 6. PIGWEED CONTROL AND GUAR TOLERANCE TO POSTEMERGENCE HERBlClDES APPLIED WHEN GUAR WAS 6 OR 10 INCHES f}
IN 1971 NEAR LUBBOCK, TEXASl - "

a’

Guar injury ("/.,) Yield ("/, reduction)
Rate Pigweed \
Herbicide (lb/acre) control ('70) 6 inches 1O inches 6 inches 10 inc 
Untreated control 0° 0° 0b O” ° ~
MSMA 2 27° 7° 20° 92°} 23“
4 70°” 3° 27° a1‘ r1
Bromoxynil 0.5 63b 7° 0b 10"
1.0 3”
Bentazone 1 .0 Oh
Chloroxuron 1.0 23° 17° 1s”
Prometryne 1.0 97° 33° 3” 20"
Methoxone 1.0 77°“ s3” 30° e2"

‘All treatments except MSMA were applied with 0.5% surfactant. Means with the same letters are not different (P<0.05).

TABLE 7. GUAR RESPONSE TO POSTEMERGENCE HERBICIDES APPLIED AT THREE DATES IN 19721

Time of treatment Mid-July evaluation
Rate 7 to Early Herbicide °/° guar
Herbicide (lb/acre) Cotyledon 10 leaves pod mean iniury’

"/0 injury after 5 days”

Untreated control O 13 17 10" 10b
MSMA 2 1o 20 20 17" 23"

4 10 33 so 34' 20"
Bromoxynil 0.5 27 43 33 34" 60“

1.0 2o 47 30 32° 73°
Bentazone 1.0 0 27 10 12" 17"
Chloroxuron + s 1.0 10 40 50 33' 47°“
Time mean 11" 32‘ 31“

Seed yield (lb./acre)

Untreated control 69 42 199 103'
MSMA 2 2s 42 11o 59°”

4 33 20 44 34"
Bromoxynil 0.5 23 22 57 34"

1.0 20 e 94 40"
Bentazone 1.0 29 35 181 82“
Chloroxuron + S 1.0 15 18 55 29b
Time mean 30" 27b 106“

‘Guar was planted May 30. Treatments were applied June 21 —— cotyledon to one true leaf, 1 inch tall; July 26 -— seven to 1O leav 
inches tall,- August 9 — 70% bloom, early pod formation on lower part of plant. Plots were two rows by 2O feet with three replicatl’
split-plot design. Plots were cultivated July 21 and August 1, hoed July 22 and hand harvested and threshed October 6 l2 rows byV
Means with the same letters are not different lP<0.05). .
"interaction between herbicides and time of treatment was significant (P<0.05).
“Average of three stages of treatment.

Guur Quality LITERATURE CITED
. l. B k,L.E. dClkH .l950.Ex '

. When gum content and protein were evaluated inrqlqeias» T632115 Agil Exgrsvtlzll Gin 1% lgegmen
1n beans frem several PrePlant and Preemergenee 2. Elder, W. C. 1962. Research on weed control in i
treatments at Lubbock in l971,'there was no indi- and improved pastures. Okla. Processed Series P41
cation that trifluralin, nitralin, alachlor or diuron 3- Elder» W- C» R- 5- Matlmk and P~ W- Santelm .1

- - Effect of several preemergence herbicides on guar, 
affected seed quality.‘ Nor was quality of seed from mungbeans and sesame_ PM; Southern weed 
plots treated with dipropetryn, an s-triazine which 83_87_ ‘-
was phytotoxic t0 guar plants, adversely affected. In 4. Hymowitz, Theodore and Ralph S. Matlock. 1

in the United States. Okla. Agr. Exp. so. Bul. 61 
5. McMurphy, W. E. 1961. The effect of 4-(2,4‘f
phenoxy) butric acid on alfalfa, cowpeas, guar, {l

these experiments, gum content of seed ranged from
43 to 48 percent, and protein ranged from 26 to 30

percent on an oven-dried basis. Consequently, it peanuts, safflower and scsamfi- MS Thesis. 0 i
appears likely that any herbicide that exhibits selec; Uni“ 
tivity for guar will not affect the gum or protein 6. Mulkey, J. R., ]r. 1971. Cotton-guar rotation. 
content. These results also show that if guar plants EXP- Sfa- P112887 I" 5°11 ‘md C”? Research l“;

- - - _ - - ing Plains. TAES Consol. PR 2884-2897. p. 32. 7
are discolored or stunted by a herbicide or s triazine 7_ Smith, D_ T_ l973_ Weeds in guan Texas Agr

I'€Sld1.lC in  Yl€lClS  b8 TCdLIC€d but SCCd P113201 In Weed and Herbicide Research in w~
quality will not be suppressed. TAES Consol. PR 3197-3207. l

l0

  

Trade name

Lasso
Evik
Basagran

Brominal,
Buctril

To-lban

Amibem

Tenoran,
Norex

Chloro IPC

Bladex

Dacthal
Cobex

Dymid,
Enide

Sancap
Karmex
Epttam
Lorox
Several
Planavin
Caparol
Ramrod

Zorial

Igran  p
Treflan

Probe

Vemam

APPENDIX ‘l

Description of Herbicides Used

Manufacturer
Monsanto
CIBA-Geigy
BASF Corp.

Amchem Products,
Rhodia

CiIBA-Geigy

Amchem Products

CIBA-Gezigy,
Nor-Am.

PPG Industries

Shell

Diamond Shamrock
U.S. Borax

Elanco,
Upjohn

CIBA-Geigy
Dupont
Stauffer
Dupont
Several
Shell
CIBA-Geigy
Monsanto

Sando-z-Wander

CiIBA-Geigy
Elanco

Velsicol

Stauffer

Chemical name
2-chloro—2',6’-diethyl-N-(methoxymethyl) acetanilide
2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine
3-isopropyl-lH-2,1,fi-benzothiodiazin-(ll)3H-one 2,2-dioxide

3,5-dibromo-Ll-hydroxybenzonitrile

N -n-propyl-N -cyclopropylmethyl-4-trifluoromethyl-2,6-
dinitroaniline

3-amino~2,S-dichlorobenzoic acid

3-[p(p-chlorophenoxflphenyl]-1,l-dimethylurea

isopropyl m-chlorocarbanilate

Z-chloro-‘l-(l-cyano-l-methylethylamino)-6-ethylamino-
s-triazine

dimethyl tetrachloroterephthalate
Nf*,1V4-diethyl-a,a,a-trifluorofi, 5-dinitrotoluene-ZA-diamine

N ,N -dimethyl-2,Z-diphenylacetamide

2~ethylthio-4,6-bis-isopropylamino-s-triazine
3-(3,4-dichlorophenyl)-1, l-dimethylurea

S-ethyl dipropylthiocarbamate
3-(3,4-dichlorophenyl)-l-methoxy-1-methylurea
monosodium methanearsonate
4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline
2,4-bis(isopropylamino)-6-(methylthio)-s-triazine
2-chloro-N-isopropylacetanilide

4-chloro-5-(methylamino)-2-(a,oz,a-trifluoromi-tolyl}
3(2H)-pyridazinone

2-(tetrt-butylamino)-4-(ethylamino)-6-(methylthio)-s-tria1ine
a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine

2-(3,4-dichlorophenyl)-4-meth.yl-LZA-oxadiazolidine-
3,5-dione

S-propyl dipropylthiocarbamate
1 1

The Texan Agricultural Experiment Station
Texan AkM University
College Station, Terms 77843

H. O. Kunkel, Acting Director- Publication

POSTAGE AND FEES PM
U.S. DEPARTMENT OF '5
AGRICULTURE
AGR 101