Method of increasing the yield of cotton plants

There is provided a method of increasing the branching, boll set or yield of cotton plants in which (3-phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid or a salt, ester or amide thereof is applied in an effective amount to the locus at which the plants are growing.

This invention concerns a method of plant growth regulation. 
(3-Phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid is a known compound, but 
hitherto its suprisingly good plant growth regulant activity with respect 
to cotton has not been appreciated. 
In one aspect, therefore, this invention provides a method of regulating 
the growth of cotton plants, in which 
(3-phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid or a non-phytotoxic 
functional derivative thereof is applied to the locus at which the plants 
are growing, in an amount sufficient to exert its plant growth regulant 
effect. 
For convenience of use, salts, especially water-soluble salts of 
(3-phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid are preferred, e.g. 
alkali-metal salts or salts with amines, and especially the sodium, 
triethylamine, tributylamine, diethanolamine and triethanolamine salts. 
Alternatively, the free acid, or esters (especially those formed with 
alkanols of 1 to 10 carbon atoms, for example the isobutyl, heptyl, 
1-methylheptyl and nonyl esters), or the amide thereof may be employed. 
The active compound may be applied to the crop in a single application, or 
in two or more discrete applications. The total rate applied is preferably 
from 1/3 oz to 4 lbs per acre, rates of 1 oz to 1 lb/acre, being most 
preferred. 
For application, the active compound is preferably formulated into an 
appropriate composition with a suitable carrier and/or wetting agent. 
Thus, the compound may, for example, be formulated into a solution or 
suspension in an appropriate liquid medium, or into a wettable powder by 
admixture with a wetting agent and, if desired, an inert diluent. Suitable 
liquid media include water (in which case the compositions preferably also 
contain a wetting agent) and water-immiscible solvents, for example high 
boiling hydrocarbons, suitably containing dissolved emulsifying agents so 
that the composition acts as a self-emulsifiable oil on addition to water. 
The liquid may be a water-miscible solvent, e.g 2-methoxyethanol, 
methanol, propylene glycol, diethylene glycol, diethylene glycol monoethyl 
ether, formamide or methylformamide. 
Inert diluents with which the compound may be admixed to form a powder 
include powdered or finely-divided solid materials such as clays, sands, 
talc, mica, peat, fertilizers and soil. If desired, the compound may be 
used to impregnate or coat preformed granules of, for example, peat or 
limestone. 
Wettable powders soluble or dispersible in water may be formed by admixing 
the compound in particulate form with a paticulate carrier or spraying 
molten compound on to the particulate carrier, admixing a wetting agent 
and a dispersing agent and finely grinding the whole powder mixture. 
An aerosol composition may be formed by admixing the compound with a 
propellant e.g a polyhalogenated alkane such as dichlorodifluoromethane, 
and suitably also with a solvent. 
A flowable suspension concentrate may be formed by grinding the compound 
with water, a wetting agent and a suspending agent. 
The wetting agents used may comprise anionic surface active agents, for 
example mono- or di-esters of phosphoric acid with fatty alcohol 
ethoxylates or salts of such esters, fatty alcohol sulphates such as 
sodium dodecyl sulphate, ethoxylated fatty alcohol sulphates, ethoxylated 
alkylphenol sulphates, lignin sulphonates, petroleum sulphonates, 
alkylaryl sulphonates such as alkyl-benzene sulphonates or lower 
alkyl-naphthalene sulphonates, salts of sulphonated 
naphthalene-formaldehyde condensates, salts of sulphonated 
phenol-formaldehyde condensates, or more complex sulphonates such as the 
amide sulphonates, e.g. the sulphonated condensation product of oleic acid 
and N-methyl taurine or the dialkyl sulphosuccinates e.g. the sodium 
sulphonate of dioctyl succinate. 
The wetting agents may also comprise non-ionic agents, for example 
condensation products of fatty acid esters, fatty alcohols, fatty acid 
amides or alkyl-substituted phenols with ethylene oxide, fatty esters of 
polyhydric alcohol esters e.g. sorbitan fatty acid esters, condensation 
products of such esters with ethylene oxide e.g. polyoxyethylene sorbitan 
fatty acid esters, block copolymers of ethylene oxide and propylene oxide, 
acetylenic glycols such as 2,4,7,9-tetramethyl-5-decyn-4,7diol, or 
ethoxylated acetylenic glycols. 
The wetting agents may also comprise cationic agents, for example alkyl- 
and/or aryl-substituted quarternary ammonium compounds such as cetyl 
trimethylammonium bromide, or ethoxylated tertiary fatty amines. 
Preferred wetting agents include ethoxylated fatty alcohol sulphates, 
lignin sulphonates, alkyl-aryl sulphonates, salts of sulphonated 
naphthalene-formaldehyde condensates, salts of sulphonated 
phenol-formaldehyde condensates, sodium oleoyl N-methyltauride, dialkyl 
sulphosuccinates, alkyl phenol ethoxylates, and fatty alkyl ethoxylates. 
The compositions which are employed may contain other active materials in 
addition to the plant growth regulants defined hereinbefore, for example 
other plant growth regulants, such as 2,3,5-triiodobenzoic acid, 
(2-chloroethyl)phosphonic acid, (2-chloroethyl)-trimethylammonium 
chloride, maleic hydrazide, N,N-dimethylaminosuccinamic acid, 
1-carboxyethyl-3-chlorocarbanilate or N-1-naphthylphthalamic acid, or 
morphactins, for example 2-chloro-9-hydroxyfluorene-9-carboxylic acid 
(methyl ester) or 9-hydroxyfluorene-9-carboxylic acid (butyl ester), 
pesticides, such as dichloro-diphenyl-trichloroethane, carbaryl or 
dimethoate; herbicides, for example 2,4-dichlorophenoxy-acetic acid, 
2-methyl-4-chlorophenoxyacetic acid, or substituted triazines or ureas, 
e.g 2chloro-4,6-bis(ethylamino)-s-triazine; or fungicides, such as copper 
compounds or dithiocarbamates. If a further active material is employed, 
it is preferably in a ratio by weight of from 1:4 to 4:1 to the plant 
growth regulants defined hereinbefore. 
The compositions which are employed are conveniently produced initially as 
concentrates for dilution before application. Such concentrates 
conveniently contain from 0.5 to 80% by weight, for example from 10 to 50% 
by weight of the plant growth regulants defined hereinbefore. 
The compositions may be applied by any method appropriate to the particular 
formulation employed, for example spraying. The concentration of wetting 
agent in the formulation applied is preferably from 100 to 4,000 parts per 
million, more preferably from 500 to 2,000 parts per million. 
The plant growth regulant effect observed is generally increased yield of 
cotton accompanied by or occasioned by increased branching and boll set. 
Thus, if the active compound is applied at the vegetative stage, i.e 
before flowering, for example at about the 6 fully expanded leaves stage, 
the main effects observed are increased branching and yield, whereas, if 
applied during flowering, e.g at first flower, or when in full bloom, the 
main effects are increased boll set and yield. A further effect may also 
be observed, namely earlier opening of the bolls. 
Application of the active compound may be made both during the vegetative 
stage and during flowering. The ratio of the rates applied at the two 
stages is desirably in the range 1:10 to 100:1, especially from 1:1 to 
4:1, e.g from 0.1 to 3.0 lb/acre at the vegetative stage, especially from 
0.25 to 1.0 lb/acre, and from 0.03 to 1.0 lb/acre, especially from 0.1 to 
0.5 lb/acre, during flowering.

The invention is further described, though only by way of illustration, in 
the following Examples. 
EXAMPLE 1 
(3-Phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid triethanolamine salt was 
applied in aqueous solution as set out in the table below at first flower 
at 1 lb/acre to Stoneville 213 cotton plants cultured individually in a 
greenhouse in 5-gallon polyvinylchloride containers filled with Bosket 
sandy loam. In each application 12 gallons spray volume per acre were 
applied. The cotton plants were planted in February and flowered during 
April and early May. The results obtained were as follows: 
______________________________________ 
Total Per Plant 
seed 
Application cotton 
When applied 
rate flowers bolls (g) 
______________________________________ 
At first 
flower 1 lb/acre 30 16 64 
At first 
flower 0 (Control) 27 14 58 
______________________________________ 
From the above, it can be seen that the number of flowers and bolls, and 
the total yield of seed cotton are increased relative to control. 
EXAMPLE 2 
(3-Phenyl-1,2,4thiadiazol-5-ylthio)acetic acid triethanolamine salt was 
applied in aqueous solution at rates of 0.128 and 0.512 lb/acre to SJ2 
Acala cotton plants grown about 6 inches apart in 30 inch spaced rows 
(about 26,000 plants per acre). Three replications were performed at each 
rate. The plants were sprayed at the early flowering stage with a spray 
volume of 56 lb/acre. 
The treatments induced additional branching, and as set out below, yield 
increases and earlier opening of the bolls relative to an untreated 
control. 
______________________________________ 
Yield % of bolls open 
lb/acre lb/acre at first picking 
______________________________________ 
0.128 1648 88.3 
0.512 1530 84.1 
0 (Control) 1380 83.9 
______________________________________ 
EXAMPLE 3 
(3Phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid triethanolamine salt was 
applied in aqueous solution at rates set out below, together with 37.5 ml 
of wetting agent X-77 (alkylarylpolyoxyethylene glycols, free fatty acids 
and isopropanol mixture by Colloidal Products Corporation) per 100 US 
gallons of formulation applied, to Coker 210 cotton plants grown in 40 
inch spaced rows and a density of about 50,000 plants per acre. The plants 
were sprayed at various times T1 (6 leaf stage), T2 (early flowering) and 
T3 (full flowering) and at various rates as set out below, there being 
four replications for each treatment. The spray volume applied was 40 US 
gal/acre. 
______________________________________ 
Treatment No. 
Time Rate (ai) (lb/acre) 
Yield (lb/acre) 
______________________________________ 
1 -- 0 (Control) 2020 
2 T1 0.25 2363 
3 T1 0.5 2297 
4 T1 1.0 2350 
5 T2 0.25 2125 
6 T2 0.5 2297 
7 T2 1.0 2455 
8 T3 0.125 2244 
9 T3 0.25 2336 
10 T3 0.5 2072 
11 T1 + T3 0.5 + 0.25 2244 
12 T1 + T3 0.5 + 0.5 2415 
13 T1 + T3 0.25 + 0.25 2521 
______________________________________ 
EXAMPLE 4 
(3-Phenyl-1,2,4-thiadiazol-5-ylthio)acetic acid triethanolamine salt was 
applied in aqueous solution at rates set out below to Coker 210 cotton 
plants grown in 40 inch spaced rows and a density of about 50000 plants 
per acre. The plants were treated at times T1, T2, and T3 as defined in 
Example 3. In addition, a nitrogen fertilizer was applied foliarly at 
mid-flowering at a rate of 20 lb/acre nitrogen. The control was treated 
also with the fertilizer. Results obtained, there being four replications 
at each rate, were as follows: 
______________________________________ 
Treatment No. 
Time Rate (ai) (lb/acre) 
Yield (lb/acre) 
______________________________________ 
1 Untreated (Control) 2297 
2 T1 0.25 2363 
3 T1 0.5 2323 
4 T1 1.0 2311 
5 T2 0.25 2469 
6 T2 0.5 2429 
7 T2 1.0 2534 
8 T3 0.125 2468 
9 T3 0.25 2297 
10 T3 0.5 2574 
11 T1 + T3 0.5 + 0.25 2429 
12 T1 + T3 0.5 + 0.5 2363 
13 T1 + T3 0.25 + 0.25 2403 
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