B-1120
May 1972

LIBRARY
Am; 2 2x 1912

Texas A&M University

COTTON RESPONSE

TO LOW RATES OF 2,4-D
AND OTHER HERBICIDES

TEXAS AdvM UNIVERSITY
THE TEXAS AGRICULTURAL EXPERIMENT STATION

H. O. Kunkel, Acting Director, College Station, Texas v

Mention of a trademark or a proprietary product does not
constitute a guarantee or warranty of the product by The Texas
Agricultural Experiment Station and does not imply its approval
to the exclusion of other products that may also be suitable.

cozvrEzvrs

   
  
  
  
  
   
  
 
 
  
   
   
  
  
    
   
   
 
 
    
 
  
  
  
  

Summary ............................................................ __ ’
Introduction ______________________________________________________ __ j
Materials and Methods .................................... 
Cotton Response to Herbicide Spray 
Cotton Response to Foliar-Applied Her ‘
Results and Discussion--.'...§f. ............................ "
Cotton Response to Herbicide Spray D 
2,4-D ........................................................ ..f
Dicamba ..... .. i
MCPA ....... .-  v
Bromoxynil and Amitrole ................. ..
Cotton Response to Foliar-Applied Her‘
2,4-D__ j
Dicamba ................................................. ..
MCPA i
Picloram..-.. .. 
Bromoxynil ............................................ ..;
2,3,6-TBA and HRS-587 ............... .. 

Lint Micronaire and Length ................. ..j
Relationship Between Estimated Injury‘
and Crop Yield ...................................... .. -
Acknowledgment ............................................. .. 5
Literature Cited 
Appendix.

S UMMAR Y

Use of hormone-type chemicals is Q
many instances to control perennial bro y‘,
species in grain sorghum. However, cot ;
damaged by spray drift when these herbici
properly applied. The objective of this g
to establish the relative toxicity of several
type herbicides to cotton. Response of i
inadvertent spray drift was evaluated ini
spray drift trials and by direct applicatii
lethal rates at various growth stages. D If
ton, in order of decreasing toxicity, was 2, i
2,4-D amine >> dicamba > MCPA > pi
bromoxynil >> 2,3,6—iTBA >- HRS—587.
of 0.1 pound per acre of 2,4—D, dicamba,
reduced lint yields 20 to 97 percent. Yield ~
most severe when cotton was sprayed u‘ ‘j
ing. However, lint quality (micronaire .
was not affected by herbicides. Mi -_
estimations of foliar damage did not pro 
estimates of actual crop losses at harvest)
ductions were consistently higher than
injury estimates. 

  
   
  
  
   
 
  
  
  
    
  
  
 
  
   
   
   
  
   
   
  
  
  
  
   
 
    
  

_, RBICIDES sucn AS 2,4-D are highly effec-
gprovide low-cost control of many annual
.= 'n sorghum (7) and other grass crops.
_ they are highly effective in controlling
l broadleaf perennials (4,5,8). However,
hormone-type chemicals in cotton produc-
 been of concern because as little as
1- per acre (lb./A) of 2,4-D has injured
),

“l broadleaf weeds are becoming more
; both cotton and grain sorghum in West
i!» increase can be attributed to less fre-
vation and reduced competition from
 following herbicide use and elimina-
l ~ hoeing.

l} y several herbicides have been developed
 useful for annual weed control in sor-
near cotton. These compounds include
f CPA and bromoxynil. New herbicides
Ag- - 'lizing small patches 0-f perennial broad-
Q ‘ 2,3,6—TBA, HRS—587 (9) and picloram.
 study showed 2,3,6-TBA to be relatively
'tton (6). Amitrole has been effective as
_' atment for perennial broadleaf weeds.
,| potential hazard from spray drift from
'e newer chemicals in areas where cotton
 has not been determined.

jective of this research was (a) to establish
4:‘ phytotoxicity and hazard to cotton from
~Ywith these materials and (b) to evaluate
‘ship between observable herbicide symp-
jy after treatment and cotton yield later
n.

 ATERIALS AND METHODS
l~ Response to Herbicide Spray Drift

 e phytotoxicity from drift of several herbi-
 aluated under three environmental condi-
1- and 1970. Pots, containing two cotton
f». , were placedi, in duplicate at 0, l0 and
' wind from where chemicals were being
 field plots. The cotton, grown in the

 associate professor, Texas A8cM University Agricul-
A and Extension Center at Lubbock, and professor,
3- Western Great Plains Research Center, Bushland,

 corrrozv RESPONSE TO LOW RATES 0F 2, 4-1)
 AND OTHER 11151231010195

D. T. Smith and A. F. Wiese*

greenhouse, was in an expanded cotyledon stage, with
true leaves being initiated. Pots were placed in posi-
tion immediately prior to spraying each treatment.
Five minutes after spraying, pots were moved to the
windward side of the field and later returned to a
greenhouse where injury to cotton was visually esti-
mated 3 weeks after treatment. Chemicals investi-
gated in this trial were 2,4—D amine, ZA-D ester,
dicamba, MCPA, bromoxynil and amitrole (Appen-
dix). All chemicals were applied at 1 pound per
acre of active ingredient in 15 gallons of water, with
0.5 percent surfactant, at 28 pounds pressure, with a
tractor-mounted plot sprayer. Wind velocities ranged
from 3 to l0 miles per hour, and air temperature
ranged from 68° to 80° F. Plots were 13.3 by 35 feet
with three replications.

In a second experiment, cotton growing in a field
was sprayed with 1 pound per acre of either 2,4—-D

amine or dicamba. At the time of application, cotton

was l2 inches tall and squaring. Soil was dry, air
temperature was 95° F and wind was 2 to 5 miles
per hour. Chemicals, replicated three times, were
applied to 30-foot sections of one 40-inch row in 30
gallons of water, at 40 pounds pressure. After ma-
turity, cotton was hand-harvested in 20 feet of the
treated row and in the three adjacent leeward rows
to evaluate spray drift.

Cotton Response to Foliar-Applied Herbicides

Relative phytotoxicity and drift hazard were
evaluated by applying low sublethal rates of several
herbicides at various stages of cotton growth (Table
l). Herbicides applied were 2,4—D amine, dicamba,
MCPA, picloram, bromoxynil, 2,3,6-TBA and HRS-
587. Chemicals were applied in 36 gallons per acre,
at low pressure (15 pounds) with three replications.

TABLE l. STAGE OF COTTON GROWTH AND APPLI-
CATION DATES WHEN LOW RATES OF HERBICIDE
WERE SPRAYED ON COTTON

Stage of cotton growth when treated

Year Presquare Square Bloom
1965 June l4 Aug ll
1966 July 8

1969 July 18 July 25 July 30

TABLE 2. PERCENTAGE INJURY FROM SIMULATED HERBICIDE DRIFT TO COTTON SEEDLINGS
AND 40 FEET DOWNWIND, UNDER THREE ENVIRONMENTAL CONDITIONS‘

  

 

 

  

1969 — 73° F 1970 —— 68° F 1970 — 80° F
3.4 to 7.9 MPH 8 to l0 MPH 4 to 6 MPH
Rate
Herbicide (lb./A) 0 l0 40 mean 0 l0 40 mean 0 10 40 mean
Untreated control 0 0 0 0° 0 0 0 0“ 0 0 0, 0“ 0
2,4-D amine’ l 100 50 20 57" 90 37 7 45" 95 45 l5; 52' 95
2,4—D ester 1 82 25 17 42“ 82 40 22“ 48“ 82
Dicamba’ 1 75 15 5 32" 82 20 0 34"’ 85 30 7 41'" 81
MCPA I 50 15 0 22”‘ 47 20 0 22° 80 10 5 32° 59
Bromoxynil l 100 22 2 42*‘ 95 27 5 42"’ 97
Amitrole 8 100 0 0 33" 100
Mean 65‘ l6" 5" 67“ 21*’ 5° 73‘ 25" 9°

 

 

‘Injury was visually estimated on plants grown in l-gallon cans in a greenhouse after seedlings were exposed while . "

plots. Means with the same letter are not different, and herbicide-drift distance interactions were significant in

(P<0.05).
‘Applied at 0.5 pound per acre in 1969.

Plots were one row by 30 feet with two untreated
rows between plots, in three replications. Injury to
cotton was estimated visually at two dates in 1969.
Lint yield and fiber quality (length and micronaire)
were determined after cotton was killed by frost in
the fall. Plots were furrow-irrigated twice in 1965
but were not irrigated in 1966 or 1969.

RESULTS AND DISCUSSION

Cotton Response to Herbicide Spray Drift

Damage from herbicides to crop plants was
readily apparent when cotton seedlings were evalu-
ated in the greenhouse (Table 2). In all three trials
cotton was most severely damaged by all chemicals
when cotton was directly sprayed (0 feet downwind).
The degree of injury to the seedlings diminished or
became nonexistent as their distance from plots ‘being
sprayed increased.

Damage to cotton depended on the distance from
the sprayed area and the chemical used. Damage to
cotton, in order of decreasing injury, was 2,4—D ester
> 2,4—D amine >> dicamba E MCPA > bromoxynil
> amitrole.

2,4-D

When’ cotton was sprayed with 2,4—D amine, plant
damage ranged from 90 to 100 percent. Damage was
most severe in low wind since the chemical was not
displaced and diluted by wind. High wind (8 to l0
miles per hour) decreased the effect of 2,4—D sprayed
directly on cotton since some of the chemical was
blown away. Plants located l0 feet away were dam-
aged 37 to 50 percent, and plants 40 feet away were
damaged 7 to 20 percent. Injury was lower when
wind diluted and displaced more of the 2,4—D spray.
Damage from 2,4-D ester to cotton 0 and 10 feet
downwind was comparable to that observed with
2,4-—D amine. However, the ester formulation re»
sulted in more damage to cotton located 40 feet away

4

   
   
   
    
 
 
 
 
 
  
  
  
   
 
  
   
   
  
  
    
 
   

than did 2,4—D amine. The difference

toxicity between the formulations was vf
evident when wind velocity was 8 to l0 f
hour. It was concluded that damage to rg
2,4—D was directly related to wind veloci»
damage from 2,4—D could be confined t0 A
ate area of application when winds were 
miles per hour). However, with in g
speeds, damage in the immediate area was
more chemical was blown away and distri
a wide area. 

k .

'

Dicamba j

Foliar damage from dicamba was n1
to air temperature than to wind velocity
tion. Damage to directly sprayed cotton 
75 to 85 percent. Cotton located l0 feet
damaged 15 to 30 percent, and cotton 
was damaged 0 to 7 percent. Injury to l
more severe when dicamba was sprayed at,
at 68° or 73° F. Response of cotton to 
to temperature differences, was particul _
on plants located l0 and 40 feet away fro
chemical was applied. However, drift -
(10 to 40 feet) was consistently less 
cotton than that of 2,4-D amine or ester;
tive safety of dicamba, in relation to 2,4-
evident in another field trial (Table 3). g
and dicamba killed cotton when the crop j p.

TABLE 3. LINT YIELD OF COTTON, l 
DOWNWIND WHEN AN ADJACENT ROW
WAS SPRAYED WITH 2,4—D OR DICAMBA 

Lint, lb./

ROWS d -' f
Treated He? ‘j
Herbicide lb. / A row l

Untreated control 224 208
2,4—D amine l 0 160
Dicamba 1 0 205

  
 
 
 
 
  
 
  
  
 
  
  
 
 
  
 
 
 
  
  
   
  
 
 
 
  

 mba did not reduce lint yield in the
 , as did 2,4-D.

 MCPA is chemically very similar to
(“chemical was consistently less toxic to
 "2,4—D (Table 2). Furthermore, MCPA
p. . 'ng than dicamba. Damage to cotton
yed with MCPA ranged from 47 to 80
_ appeared to be related to air temperature
gof application. Only minor damage (10
i- t) occurred on cotton located 10 feet
Qsand no significant damage was observed
 wind from the sprayed area. Of the

herbicides investigated, MCPA ap-
 A the least hazardous for use around cotton

41

A and Amitrole

f ynil was highly toxic if sprayed directly
 Foliage and stems were completely desic-
 ;- on cotton located l0 feet downwind
i 'ght1y damaged (22 to 27 percent) while
-j7n0t occur on plants 40 feet downwind. In
gjury from amitrole was limited to those
 y sprayed. There was no evidence of
' g drift from amitrole.

y

Cotton Response to Foliar-Applied Herbicides

Damage to cotton increased as application rates
increased; however, a fivefold or tenfold increase in
rates did not result in a fivefold or tenfold increase
in cotton damage (Table 4). Yield losses were gen-
erally most severe from herbicides applied when cot-
ton was in a vegetative state and actively growing
(presquare and square stages). Less herbicide damage
occurred after cotton bloomed when bolls were de~
veloping and plants were less vegetative and not
growing rapidly.

Herbicide toxicity was in the same relative order
in reducing cotton yields as it was in damaging cotton
in simulated drift trials (Table 4). Herbicides that
decreased lint yield, in order of decreasing toxicity,
were 2,4—D >> dicamba > MCPA > picloram >>
bromoxynil >> 2,3,6—TBA E HRS~587.

2,4-D

Application of 0.05 and 0.1 pound per acre of
2,4—D on cotton foliage caused significant yield losses
each year. Yield reductions ranged from 32 to 81
percent, averaging all application dates. Spraying
0.01 pound per acre of 2,4—D did not cause losses
that were statistically significant; however, yields were
consistently 7 to 32 percent lower than those of un-
treated controls. The earlier the cotton was sprayed

A T YIELD OF COTTON FOLLOWING FOLIAR APPLICATION OF LOW RATES OF HERBICIDES AT VARIOUS

 

5 AGES‘

 

    
 

   

"

‘K.

 ->-

1965 1966 1969
Rater
 a (lb. / A) Square Bloom Mean Square Presquare Square Bloom Mean
 .1 ./A) of
 . control 805 912 859' 149"“ 103 203 93 133‘
Percent reduction in yield-compared to untreated controls above

0.01 25 7 15”" 28°‘ 32 25 10 22”“
0.05 57 10 32°‘ 81¢ 94 76 54 7 5‘
0.10 78 23 49“ 79‘ 97 79 49 77 f
0.01 +4 7 3" + 107 ‘ 79 38 +46 69*“
0.05 24 l4 19"" 5'“ 84 55 l1 53*‘
0.10 61 27 43'" 20°‘ 91 76 69 78'
0.01 +15“ +4 70 +31 27"“
0.05 + 12'" 75 57 +46 38M’
0.10 49" 75 62 16 504"‘
0.01 4 14 8' +16"

0.05 16 15 16"“ 52“

0.10 56 24 44“ 818

0-01 +4"'° +9 25 27 22"”
0.05 +20“ 56 48 66 544-‘
0.10 24d“ 38 78 68 65°‘
0.01 +2 19 9" + 30 29 6 8""
0.05 6 14 10" 3 19 +1 11"’
0.10  ' l0 11 11“ + 34" 32 40 3 69*“
0.10 i +2 8 3‘ 17°“

0.20 6 11 8"

24" 15" 45" 51“ 20"

 -_~ (+) indicate yield increase above untreated controls; all other values are ‘Z, loss. Interactions between herbicide
d time of application were significant in 1965 and 1969 (P<0.05). Means followed by the same letter are not differ-

5

the more severe was its damage. The increased
susceptibility of seedling cotton to 2,4—D was readily
apparent in the 1969 trial. There was no indication
of increased cotton yield due to low rates of 2,4—D
since the rates investigated were probably above the
ultra-low levels required for beneficial growth stimu-
lation.

Dicamba

Application of 0.1 pound per acre of dicamba
consistently reduced cotton yields, and losses gen-
erally ranged from 27 to 91 percent. Reduction in
lint production was greatest in 1969. As in results
with 2,4—D, yields were reduced most when cotton
was sprayed early in the year. However, losses oc-
curred when the highest application rate (0.1 pound
per acre) of dicamba was applied at cotton bloom.
In three instances yields appeared to be enhanced
from dicamba applied at 0.01 pound per acre. How-
ever, this rate also reduced yields 3 to 79 percent at
other times.

MCPA

The visual response of cotton to MCPA was
similar to that of 2,4—D, although yields were not as
drastically reduced by MCPA. Damage to cotton
decreased with increased plant age. Seedlings sus-
tained the most damage, but injury was insignificant
on older plants. In five of eight instances, yields
were not decreased at all by MCPA at 0.01 or 0.05
pound per acre. The sodium salt of MCPA was less
toxic to cotton than the formulation of 2A-D or
dicamba used in these tests.

Picloram

This herbicide is highly effective on many
perennial broadleaf weeds since the chemical persists
and moves in the soil. Picloram at 0.01 pound per
acre did not reduce yields compared to the untreated
check. However, yields were consistently lowered
following application of 0.1 pound per acre regard-
less of the growth stage. Legume, solanaceous and
other crops are considerably more sensitive to picloram
than is cotton. Consequently, picloram should be
used with extreme caution around soybeans, peas,
beans, tomato, potato, pepper, egg plant, cucumber,
watermelon, cantaloupe and other crops. Sensitive
crops should-not be planted in fields where runoff
or tailwater from treated fields may flow. Direction
and flow of runoff water should be determined before
picloram application.

Bromoxynil

Bromoxynil, a contact-type herbicide, was highly
toxic to cotton in 1969 when applied at 0.05 or 0.1
pound per acre. The chemical tended to cause more
damage on old than on young plants. However,
bromoxynil would be safe to use around cotton fields
since damage would be limited to plants in direct
contact with the spray.

 
  
   
 
 
 
  
   
    
   
  
   

2,3,6-TBA and HRS-587 ,

These chemicals had little or no adverse.
on cotton. In 1969, 2,3,6—TBA reduced yields
applied at 0.1 pound per acre on cotton before *
ing. However, these chemicals could gene
used with adequate safety for perennial weed ~f
around fields without danger to cotton. l

Lint Micronaireland Length

In contrast to yields, application of he
generally had little or no effect on lint quality
5). However, some differences between s I
application and between herbicides were -;
Lint quality was suppressed most when chemi l
applied before blooming-in the presquare or.
stages. This was most apparent in micronaire‘
in 1969. '

In most instances, all application rates of
at all stages tended to lower micronaire. The‘
tion was in high-yielding irrigated cotton i
The low rate of 2,4-D (0.01 pound per acre)
detrimental as 0.1 pound per acre. However,
did not affect fiber length. l

   
   
  
  
 
  
 
  
  
   
 
  
 
  
  
   
 
  

Dicamba reduced micronaire most when 5
at 0.1 pound per acre or at presquare or square I
stages. There was little or no reduction in mi
when dicamba was sprayed when cotton was blj
In contrast, MCPA affected micronaire mos
applied to seedling cotton (presquare), -- - v5.
the rate applied. ‘

Picloram had little or no influence o)
quality, except when applied at 0.1 pound ~-
when cotton was squaring. Micronaire was
but fiber length was not affected. Bromox 
fered from other herbicides in that it e y
micronaire with later stages of application. a
naire was lowered following application of 0.1»
per acre of bromoxynil at squaring or bloo
1969. The safest compounds investigated, 2,3,;
and HRS—587, did not reduce fiber quality.
when 2,3,6—TBA was applied at 0.1 pound 
in 1969. I

Relationship Between Estimated Inj
and Crop Yield

Since fiber quality was affected to only 
extent by chemicals, the primary economic A
posed by herbicide drift was yield reductij
1969 foliar damage to cotton was estimated _‘
on July 30 and August 15 following app
Yield losses in 1969, due to chemical treatm ‘
greater than in other years. Injury estima 
not made in 1965 and 1966. ~

The highest estimates of crop damage wi 
MCPA and dicamba were in cotton evaluated":
after chemicals were sprayed on seedling (p ‘
cotton (Table 6). Chemical injury ranged f 

ma.

  

1 CRONAIRE AND LENGTH OF COTTON LINT FOLLOWING APPLICATION OF LOW RATES OF HERBI-
QARIOUS GROWTH STAGES‘

Micronaire Length (32nds of an inch)
1965 1966 1969 1965 1966
Rate
(lb. / A) Square Bloom Square Presquare Square Bloom Mean Square Bloom Square

l 3.2 3.7 4.1 4.2 4.3 4 0 4.2‘ 30 29 30
0.01 3.3 3.0 3.0 3.7 4.2 4 1 4.0”" 29 30 33
0.05 3.2 3.6 3.8 3.5 3.6 3.7 3.6”‘ 29 30 32
0.10 3.4 3.7 4.2 2.9 3 6 3.9 3.5"“ 30 29 31
0.01 3.0 3.7 4.2 2.6 4.1 4.0 3.6M‘ 30 30 32
0.05 3.2 3.4 3.8 2.4 4.2 4.0 3.5"“ 30 30 32
0.10 2.9 3.6 3.7 2.1 3.5 3.8 3.2° 29 29 32
0.01 4.2 4.0 4.0 3.9 4.0”“ 34
0.05 4.5 3.6 4 5 4.2 4.1'-° 30
0.10 4.1 3.7 4 3 4.2 4.1"” ' 33
0.01 3.2 3.4 4.0 29 30 32
0.05 3.3 3.6 3.8 30 30 32
0.10 2.7 3.8 3.8 29 30 32
0.01 4.1 4.4 4.3 4.1 4.2‘ 32
0.05 3.9 4.0 4.2 3.8 4.0"‘ 32
0.10 4.2 4.6 3.9 3.8 4.l"° 34
0.01 3 5 3.6 4.3 4.2 4.0 4.1"’ 29 30
0.05 3 8 4.0 4.2 4.2 4.3 4.2‘ 29 29
0.10 3 4 3.7 4.5 3.8 4.0 3.7 3.8"’ 29 30 32
0.10 3 4 3.5 4.3 30 29 32
0.20 3 4 3.4 30 29

3.5” 4.0‘ 4.0‘

  
  
   
 

Aland was highest where 2,4—D or MCPA at
 r acre was applied. The apparent foliar
 s. "a considerably by 28 days after pre-
 1 was sprayed. When cotton was sprayed

j ble only for 1969. Means with the same letter are not different (P<0.05).

at square or blooming stages, estimates of crop injury
were substantially lower (generally 0 to 38 percent)

' than following treatment of presquare cotton. Injury

and yield reduction with bromoxynil were about

i» IMATED INJURY TO COTTON FOLLOWING HERBICIDE APPLICATION IN 1969 IN RELATION TO
LINT YIELD AT HARVEST‘

 

Presquare Square Bloom
Rate % injury % loss % injury ‘Z, loss % injury % loss
(lb./ A) 12 days 28 days in yield 5 days 20 days in yield at 16 days in yield

‘ . 1 0 0 0 0 0 0 0 0
'  0.01 7 5 32 0 ‘ 2 25 5 10
0.05 35 l7 94 5 8 76 8 54

0.10 70 28 97 7 13 79 17 49

0.01 8 8 79 3 7 38 0 +46

0.05 25 8 84 3 8 55 0 ll

0.10 18 23 91 8 8 76 0 69

0.01 5 12 +4 12 7 70 0 +31

0.05 33 30 75 7 17 57 0 +46

0.10 75 40 75 13 27 62 l0 16

0.01 32 3 +9 15 15 25 10 27

0.05 45 45 56 23 23 48 38 66

0.10 50 48 38 38 35 78 72 68

0.01 2 5 +30 5 0 29 0 6

0.05 8 5 3 2 2 19 0 +1

0.10 7 10 32 5 3 40 0 3

25 18 45 8 l0 51 9 20

  
 

 r untreated controls.

‘l-< for presquare, square and bloom applications were July 18, July 25 and July 30, respectively.
 30 (presquare and square stages) and August 15 (presquare, square and bloom).

Injury was visually
Positive values (+) indicate yield

7

equal. Estimated injury and yield loss were low with
2,3,6-—TBA. " - 

There was no consistent relationship between
visual estimates of‘ percentage injury to cotton and
actual yields. In some instances low estimates of
injury (40 percent or less) were followed by high
reduction (60 percent or more). in crop yield. This
was particularly true" for dieainba, 2.4.20 and MCPA
applied at 0.05 pound per acre or more to cotton in
the presquare or square stages. With this rate at
the square stage of treatment, all estimates of crop
damage were low (less than 27 percent) while actual
yield losses were generally high (55 percent or more).
For example, injury from 0.0.5 pound per acre was
estimated at 8 percent, but yield loss was 76 percent.

These data show that it is extremely difficult
to predict accurately the extent of crop loss from
herbicide drift prior to the time of actual harvest.
Therefore, portions of cotton fields that appear to
be damaged from inadvertent chemical drift should
be clearly marked and identified. Then “damaged”
and known untreated areas should be harvested sepa-
rately to accurately assess the magnitude of actual
crop loss. In most instances cotton could be har-
vested by hand from different areas in the same field
for comparison to determine whether economic crop
damage actually occurred.

APPENDIX

SUMMARY OF HERBICIDES INVESTIGATED FOR SPRAY DRIFT DAMAGE TO COTTON IN WEST TEXAS A

  
 
  
 
   
  
 
  
  
   
   
   
  
  
 
 
   

ACKNOWLEDGMENT ;

This research was supported by Plai z
Growers, Inc., Lubbock, Texas, and by C0 f
Raleigh, North Carolina. 

LITERATURE CITED

1. Behrens, R., W. C. Hall and C. E. Fisher. j
responses of cotton to four phenoxy type herbi
SWC. 8:72—-75. ' l; 

2. Ergle, D. R. and A. A. Dunlap. 1949. n: i
to 2,4—D. Tex. Agr. Exp. Sta. Bul. 713. ‘

3. Porter, W. K., C. H. Thomas and J. B. Baker;
three-year study on the effect of some phenox i.
on cotton. Weeds. 72341-348.

4. Smith, D. T. 1970. Texas blueweed control g
type herbicides, amitrole-T and tillage. Texas.
Sta. Progress Report. 2848. f

5. Wiese, A. F. 1967. Perennial weed control in
Texas. Tex. Agr. Exp. Sta. MP—828. i

6. Wiese, A. F. and A. c. Martin. 196s. Toxi’ ’
acid herbicides to cotton and soybeans. W a M

7. Wiese, A. F. and H. E. Rea. 195s. Trea’
sorghum with 2,4—D. Agron. _]. 50:309-310. j

s. Wiese, A. F. and H. E. Rea. 1959. Bindweed 
aruensis L.) control and seedling emergence as.
tillage, 2,4—D and competitive crops. Agron. 1.":

9. Wiese, A. F. and H. E. Rea. 1961. Control F
weed and other perennial weed with benzoic j
acetic acids. Weeds. 9:423—428. i

 
  

Chemistry and Formulation

TO 1970
Common Trade
name name‘ Supplier

2,4—D amine Formula 40 Dow
2,4—D ester Weedone LV4 Amchem.
Dicamba Banvel Velsicol
MCPA Chiptox Rhodia
Bromoxynil r Buctryl Rhodia
Amitrole Amitrol-T Amchem
Picloram Tordon 22K Dow
2,3,6—TBA Trysben 200 Dupont
HRS—587 Tritac Hooker

isopropanol-ethanol amine of Zxkdichlorophenox .- -_
butoxyethanol ester of 2,4——dichlorophenoxyacetic acid ..
dimethylamine salt of 2—methoxy—3,6—dichlorobenz0ic f
sodium salt of 2—methyl—4-chlorophenoxyacetic acid "
3,5—dibromo-Il-hydroxybenzonitril

3—arnino~s—triazole + ammonium thiocyanate ,_
potassium salt of 4—amino—3,5,6—trichloropicolinic aci A‘
2,3,6—trichlorobenzoic acid '
2,3,6-trichlorobenzyloxypropanol

 
   
    
 

,-

‘2,4—D also sold as Weedar, Dacamine and numerous other trade names.
MCPA (Amchem), Brominal (Amchem) and Cytrol (American Cyanamid).

MCPA, bromoxynil and amitrole also _~ i,