GB2031279A

GB2031279A - Herbicides

Info

Publication number: GB2031279A
Application number: GB7924150A
Authority: GB
Original assignee: Lilly Industries Ltd
Current assignee: Lilly Industries Ltd
Priority date: 1978-07-15
Filing date: 1979-07-11
Publication date: 1980-04-23
Also published as: BE877675A; GB2031279B; CS209930B2; JPS5515483A; CA1129664A; ZA793515B; GB2027344A

Abstract

The selective control of weeds in post-emergence treatment of cereal crops employing a combination of a compound of formula I <IMAGE> and a compound of formula II <IMAGE> wherein X is -CH(CH3)-, -CH2- or -(CH2)3- the treatment being shown to be synergistic, particularly in controlling the problematic weed species Matricaria spp.

Description

1 1 9 5 GB 2 031 279 A -1

SPECIFICATION Herbicides

The invention relates to a method of combating weeds in cereal crops and to herbicidal formulations for use in such method.

Heretofore, the broadleaf weed species Matricaria spp has proved particularly resistant to 5 conventional herbicides, causing much damage to winter and spring cereal crops such as wheat, barley, oats and rye. We have now found that by using a combination of particular known herbicides this weed species is controlled to a surprisingly high level, synergism, in accordance with the well-known "Colby Equation" (Weeds, 15, 20-22, 1967), being observed. Additionally, control of other problematic weed species has been found to be very satisfactory when using the combination, synergism again being 10 observed in several cases.

Thus, according to the present invention a method of combating weeds in a cereal crop locus comprises applying to said locus, post emergence the crop, a compound of formula 1, 0 CH A cl 02N __---1 a cl (1) and one or more compounds of formula 11, wherein CH3 cl 0-X-COOH X is -CH(CH,)-, -CHi-- or -(CH,),r-; where a compound of formula 11, in which X is -CH(CH3)-, is employed, the compound of formula 1 being applied at a rate of 0.25 to 3.0 kg/ha and the compound of formula 11 being applied at a rate of 0.5 to 3.0 kg/ha; where a compound of formula 11, 20 in which X is -CH27-, is employed, the compound of formula 1 being applied at a rate of 0.7 to 2.0 kg/ha, and the compound of formula 11 being applied at a rate of 0.7 to 3. 0 kg/ha, and where a compound of formula 11, in which X is -(CH2)-, is employed, the compound of formula 1 being applied at a rate of 0.25 to 3.0 kg/ha and the compound of formula 11 being applied at a rate of 0.1 to 3.5 kg/ha, the crop being other than spring wheat where a single compound of formula 11, wherein X is 25 -CH(CH,)-, is employed.

In general, the compound of formula 1 is applied at a rate of from 0.7 to 2.0 kg/ha and the compound(s) of formula 11 at a rate of from 0.7 to 3.0 kg/ha.

The compound of formula 1 is known as bifenox, the preparation thereof being described in United Kingdom Patent Specification No. 1,232,368 and its use as a herbicide being described in Proc. N. E. 30

WeedSciConf 1973,27,31.

The compound of formula 11, wherein X is -CH(CH3)-, is known as mecoprop.

The compound of formula 11, where X is -CH2-, is known as M.C.P.A.

The compound of formula 11, wherein X is -(CH,)g--, is known as M.C.P.B.

Mecoprop, M.C.P.A., M.C.P.B., their salts and esters, their manufacture and their herbicidal 35 properties are well documented in the literature.

The compounds of formula 11 may be employed in free acid form or in a salt or ester form which is non-phytotoxic to cereals. As examples of salts forms may be given the alkali-metal, e.g. sodium and potassium, salt forms and the ammonium, alkylammonium and alkanolammonium salt forms, e.g. the ethanolammonium salt form. As examples of ester forms maybe given the lower, e.g. Cl-, alkyl ester 40 forms, e.g. the methyl and octyl ester forms. The use of such salts and ester forms is embraced by the present invention.

In the method of the present invention, the compound of formula 1 (bifenox) is preferably employed at an application rate of from 0.7 to 1.5 kg/ha and more preferably at a rate of about 0.75 to 1.0 kg/ha.

The compounds of formula 11, wherein X is -CH(CH3)- or -(CH2),7-, i.e. mecoprop or M.C.P.B., is 45 preferably employed at an application rate of from 1.0 to 2.0 kg/ha. The compound of formula 11, wherein X is -CHI--, i.e. M.C.P.A., is preferably employed at an application rate of from 0.7 to 1.5 kg/ha and more preferably at a rate of about 0.75 to 1.0 kg/ha.

The weight ratio of the compound of formula 1 to the compound(s) of formula 11 is generally in the 2 GB 2 031 279 A 2 range of from 1:4 to 3A. Where the bifenox is employed together with mecoprop or M.C.P.B., the weight ratio of the former to the latter is preferably in the range of from 1:3 to 1.5A, more preferably about 12. Where the bifenox is employed together with M.C.P.A., the weight ratio of the former to the latter is preferably in the range of from 1:2 to 2A, more preferably about 1A.

In the case of the compounds of formula 11, the above weights and ratios are based on the acid 5 equivalent thereof if a salt or ester is employed.

The method of the present invention is preferably carried out when the crop is between the one leaf stage and appearance of the second node.

The preferred crops for treatment by the method of the present invention are winter wheat, spring barley and winter barley.

The compound of formula I and the compound(s) of formula 11 may be applied together or separately. If the latter, the time period between applications is preferably short, say one day or less. It is by far preferred, however, for the compounds to be applied simultaneously as a single formulation. In order to simplify manufacture, storage and transport, herbicidal formulations will normally be produced in concentrate form intended for dilution in water to the degree necessary to enable the above application rates to be achieved. Such concentrate formulations may contain from 1 to 90%, preferably to 85%, by weight of active ingredients associated with one or more inert, non-phytotoxic, carriers therefor. Such formulations will usually be in the form of a wettable powder, an emulsifiable concentrate or an aqueous suspension or solution.

Herbicidal formulations form a further aspect of the present invention. Thus, there is provided a 20 herbicidal formulation to be used in the method of the invention, after dilution if appropriate, and comprising a compound of formula I and one or more compounds of formula 11, or a salt or ester thereof, in a weight ratio range of from 1:4 to 3:1 (based on the acid equivalent of the compound(s) of formula 11) together with a non-phytotoxic diluent or carrier. The preferred weight ratio ranges are as given above.

As a further separate aspect of the present invention, there is provided a herbicidal formulation comprising a compound of formula 1, stated above, together with a compound of formula 11, in which X is -(CH,),-, or a salt or ester thereof, in a weight ratio range of from 1:4 to 3:1 (based on the acid - equivalent of the compound of formula 11), together with a non-phytotoxic diluent or carrier. Again, the preferred weight ratio ranges are as given above.

The herbicidal formulations of the present invention are intended to embrace not only the so called concentrate formulation forms, but also ready-to-use dilute formulations such as tank mixes and application spray liquors. Such dilute formulations are generally produced by dilution down to the appropriate degree of concentrate formulations but, if desired, may be produced by the separate addition of appropriate amounts of the individual components to an appropriate diluent or carrier.

Turning, however, to the concentrate formulations, wettable powders comprise an intimate mixture of the active ingredients, one or more inert carriers and one or more appropriate surfactants.

The inert carrier may be chosen from the attapulgite clays, the montmorillonite clays, the diatomaceous earths, kaolins, micas, taIcs and purified silicates. Effective surfactants may be found among the -sulphonated lignins, the naphthalene sulphonates and condensed naphthalene sulphonates, the alkyl 40 succinates, the alkylbenzene sulphonates, the alkyl sulphates and non- ionic surfactants such as ethylene oxide adducts of phenol. Illustrative wettable powders are those having the following composition:

WETTABLE POWDERS 4 % by weight 45 Compound of formula 1 Compound of formula 11 Surfactant(s) 1 to 73 Dispersing Agent Anticaking Agent Inert carrier(s) based on acid equivalent 1 to 79 1 to 10 Oto 10 Oto 10 to 100 Emulsifiable concentrates comprise the active ingredients dissolved in one or more suitable solvents, together with a surfactant. As examples of solvents may be given alkyl substituted benzenes, 55 o-chlorotoluene, heavy aromatic naphthalenes, glycol ethers and cyclic ketones. Illustrative emulsifiable 55 3 concentrates are those having the following composition:

EMULSIFIABLE CONCENTRATES Compound of formula 1 Compound of formula 11 Surfactant(s) Co-solvent Solvent Based on acid equivalent GB 2 031 279 A 3 % weight/volume 1 to 55 1 to 60 2 to 10 0 to 40 to 100 Aqueous suspensions and solutions comprise the active ingredients suspended or dissolved in 10 water together with any desired surfactants, thickening agents, antifreezing agents or preservatives. Suitable surfactants may be chosen from those mentioned above in connection with wettable powders. Thickening agents, if used, are normally chosen from appropriate cellulose materials and natural gums, whilst glycols will generally be used when an antifreezing agent is required. Preservatives may be 15 chosen from a wide range of materials such as the various paraben antibacterials, phenol, ochlorocresol, phenyl mercuric nitrate and formaldehyde. Illustrative aqueous suspensions are those having the following composition:

AQUEOUS SUSPENSIONS % weight/volume Compound of formula 4 to 59 20 Compound of formula 11 5 to 65 Wetting Agent 0 to 10 Dispersing Agent 0 to 6 Thickening/Suspending Agent 0 to 5 Antifreeze Agent. 0 to 15 25 Preservative 0 to 2 Water to 100 Based on acid equivalent The aqueous suspension and wettable powder formulations are preferred for use in the method of the present invention, giving significantly lower phytotoxicity to the cereal crop than the emulsifiable 30 concentrate formulations.

The following Examples further illustrate the inventions. In all Examples, the amount of mecoprop, M.C.P.A. and M.C.P.B. used is based on the acid equivalent.

EXAMPLES 1 TO 5 The following wettable powders were prepared, in each case having the ingredients shown: 35 % by weight (1) Bifenox Mecoprop (potassium salt) 4 GB 2 031 279 A 4 Sodium lauryl sulphate 3 Sodium lignin sulphonate 3 Precipitated silica 8 Kaolin to 100 % by weight 5 (2) Bifenox 20 Mecoprop (Sodium salt) 27 Ethoxylated alkyl phenol 4 Lignosulphonate 3 Fumed Silica 6 10 Attapuigite to 100 % by weight (3) Bifenox Mecoprop (diethanolamine salt) Sodium salt of condensed naphthalene sulphonic acids Precipitated silica Sodium alumino silicate 25 6 10 to 100 % by weight (4) Bifenox 30 20 M.C.P.B. (sodium salt) 45 Sodium lauryl sulphate - 2 Sodium lignin sulphonate 3 Precipitated silica 5 Montmorillonite to 100 25 % by weight (5) Bifenox 30 M.C.P.A. (sodium salt) 30 Sodium lauryl sulphate 2 Sodium lignin sulphonate 3 30 Precipitated silica 5 Montmorillonite to 100 1 GB 2 031 279 A 5 In each Example, the active ingredients were carefully blended with the specified ex1pients in conventional mixing equipment. The blend was then further milled in a fluid energy mill to a size range of from 1 to 10 microns.

EXAMPLES 6 TO 10 The following emulsifiable concentrates were prepared having the constituents shown below: 5 % by weight/ by volume (6) Bifenox 15 Mecoprop 30 Calcium dodecylbenzone sulphonate 3 10 Alkyl phenoxypolyoxyethylene ethanois 3 Isophorone 20 Xylene to 100 % by weight/ 15 by volume (7)13ifenox 15 Mecoprop ester 20 Alkyl aryl sulphonate 4 Polyoxyethylene triglyceride 4 20 Cyclohexane 20 Orthochlorotoluene to 100 % by weight/ byvolume 1 (8) Bifenox 10 25 Mecoprop 25 Amine salt of dodecylbenzene sulphonic acid 3 Polyoxyethylene sorbital fatty esters 4 30 Isophorone 15 Heavy aromatic naphtha to 100 6 GB 2 031 279 A 6 % by weight/ byvolume Bifenox M.C.P.B. (mixed butyl esters) Calcium dodecy[benzene sulphonate Alkyl phenoxypolyoxyethylene ethanols lsophorone Orthochlorotoluene 30 3 4 30 to 100 % by weight/ 10 by volume (10) Bifenox 20 M.C.P.A. 20 Calcium dodecylbenzene sulphonate 3 15. Alkylphenoxypolyoxyethylene 15 ethanols 4 lsophorone 30 Orthochiorotoluene to 100 The active ingredients were added to the appropriate solvent(s) with stirring and optional heating to facilitate dissolution of the active materials. The surfactants were then added. The solutions were 20 then filtered to remove insoluble impurities.

EXAMPLES 11 TO 13 The following aqueous suspensions were prepared having the constituents shown below:

% by weight j (11) Bifenox 30 25 M.C.P.A. hamine salt) 30 (Ethyl) hydroxyethyl cellulose 0.2 Lignin sulphonate 3 Propylene glycol 2 x Water to 100 30 % by weight (12) Bifenox M.C.P.B. (amine salt) Hydroxyethyl cellulose Amine ethoxylate Water 35 0.2 3 to 100 7 GB 2 031 279 A 7 (13) Bifenox Mecoprop (amine salt) Hydroxyethyl cellulose Phosphate ester Ethylene glycol Water % by weight 0.5 3 2 to 100 The following Examples serve to illustrate the synergistic effect demonstrated by the method of the invention.

EXAMPLE 14

Several field trials were carried out on winter wheat and one on spring barley on sandy and clay loam soils. Applications was made as tank mixtures with a knapsack sprayer at a volume of 300-800 I/ha. The crop stage at application varied from the start of tillering to the stage at which the second node was visible. Visual assessments of herbicidal activity were made from 2 to 15 weeks after application using the Barratt and Horsfall (1945) rating system.

In the following table is set out the average of the results obtained in terms of percent control of the weed species Matricaria spp for the individual herbicides Bifenox, mecoprop and M.C.P.A. and for the tank mix combinations of Bifenox + mecoprop and Bifenox + M.C.P.A., there also being given the control value estimated by the Colby formula for additive effect. The concentrates from which the aqueous spray liquors were formed were Bifenox 80% wettable powder, mecoprop 55% aqueous solution and M.C.P.A. 40% aqueous solution.

TABLE % Control Dosage Rate Kg/ha Observed Colby formula Bifenox 1.0 16.1 N/A Bifenox 1.5 25.5 N/A Bifenox 2.0 40.3 N/A M.C.P.A. (amine salt) 0.8 38.5 N/A M.C.P.A. (amine salt) 1.6 64.8 N/A Mecoprop (amine salt) 2.0 54.8 N/A Bifenox + M.C.P.A.

(amine salt) 1.0+0.8 85.1 48.4 1.5+0.8 93.4 54.2 2.0+1.6 95.3 79.0 Bifenox + mecoprop (amine salt) 1.0+2.0 86.0 62.1 1.5+2.0 89.0 66.3 8 GB 2 031 279 A 8 Thus, from the above it can be seen that a genuine synergistic effect is observed when employing the method of the present invention.

Slight scorching of the crop was noted, which was subsequently out-grown.

As well as excellent control of the Matricaria spp, the following weed species were well controlled (greater than 80%) employing, in separate tests, the above combined tank mixes: Anethum graveolens, 5 Capsella bursa-pastoris, Centaurea cyanus, Fumaria officinalis, Lamium amplexicaule, Papaver rhoeas, Silene spp and Stellaria media..

The Bifenox + M.C.P.A. combination additionally gave good control (greater than 80%) of the following weed species. Anagallis arvensis, Chenopodium album, Polygonum aviculare Ranunculus arvensis, Ranuncules repens, Raphanus raphanistrum, Rumex crispus, Sinapis arvensis, Sonchus 10 arvensis and Veronica hededfolla.

The Bifenox + mecoprop combination additionally gave good control (greater than 80%) of Gallum aparine.

EXAMPLE 15

The following greenhouse test was carried out to assess the efficacy of bifenox combined with 15 M.C.P.B.

METHOD Seeds Gaflum aparine Matricaria recutita Veronica persica 20 1 Planting.. 0.5 cm depth. (Matricaria sp light covering) Temperaturellighting: Greenhouse (cool) Watering.. when required Fertilisation: none Experiment design: randomised block (4 replicates) 25 Plot size treated.. 10 x 10 cm pots Soil texture: loam Application equipment., single nozzle microsprayer, 50 cm band width, volume rate per area 50 mi per sq metre.

Weed Stage atApplication: 3-5 true leaves. 30 In the following table is set out the average of the results obtained in terms of per cent control of the weed species, together with the control value estimated by the Colby formula. For the Veronica persica a visual control rating was made. For the other two species fresh weight of shoots was obtained. The bifenox from which the spray liquor was formed was an 80% wettable powder, the M.C.P.B. was a 35 48% aqueous solution, the combination being a tank-mix.

4 9 GB 2 031 279 A 9 WEED SPECIES, % CONTROL Rate Matricaria Sp Gallum aparine Versonica persica kg/ha Observed Colby Observed Colby Observed Bifenox: 0.75 56.5 N/A 62.5 N/A 77.0 M.C.P.B. 1.0 7.5 N/A 0.0 N/A 73.0 M.C.P.B. 1.5 2.4 N/A 0.0 N/A 78.0 Bifenox + MCPB 0.75+1,0 73.0 60.0 72.1 62.5 100.0 11 0.75+1.5 82.0 57.5 78.3 62.5 100.0 Colby N/A N/A N/A 94.0 96,0 Thus, from the above, it can be seen that a genuine synergistic effect is observed when employing the method of the present invention.

EXAMPLE 16

This example further illustrates the synergistic effect demonstrated by the combination of bifenox + mecoprop when used for control of the broadleaf weed Matricarla spp.

Winter wheat was sown in France in October at a depth of 3 cm. and at a rate of 150 kg/hectare.

The crop was allowed to grow without treatment until the following March, at which time the crop was at growth stage 4-5 (see Plant Pathol., 3 128-9, (1954)).

Bifenox and mecoprop were then applied separately and combined together as a tank mix and 10 sprayed onto the area in which the crop was growing using a knapsack sprayer at a volume rate per hectare of 300 litres. Assessments, as weed control ratings, were made between 2 and 5 weeks after application.

TABLE

Dosage rate Matricaria spp g/hectare % control Bifenox 1000 6 Bifenox 1500 15 Bifenox + Mecoprop 1000 +2000 87 Bifenox + Mecoprop 1500 +2000 88 Mecoprop 2000 50

Claims

1. A method of combating weeds in a cereal crop locus comprising applying to said locus, post emergence the crop, a compound of formula 1, 0 CH3J, cl 02N 0 - cl (1) GB

2 031 279 A 10 and one or more compounds of formula 11 wherein C11 3 cl _ 0-X-COGH X is -CH(CH3)-, -CH2 or -(CH2)37-, where a compound of formula 11, in which X is -CH(CH3)-, is employed,-the compound of formula 1 being applied at a rate of 0.25 to 3.0 kg/ha and 5 the compound of formula 11 being applied at a rate of 0.5 to 3.0 kg/ha; where a compound of formula 11, in which X is -CHI-- is employed, the compound of formula 1 being applied at a rate of 0.7 to 2.0 kg/ha and the compound of formula 11 being applied at a rate of 0.7 to 3. 0 kg/ha, and where a compound of formula 11, wherein X is -(CH2)j-, is employed the compound of formula 1 being applied at a rate of 0.25 to 3.0 kg/ha and the compound of formula 11 being applied at a rate of 0. 1 to 3.5 kg/ha, 10 the crop being other than spring wheat where a single compound of formula 11, wherein X is -CH(CH3)-, is employed. - 2. A method according to claim 1, wherein the compound of formula 1 is applied at a rate of 0.7 to 2.0 kg/ha and the compound(s) of formula 11 at a rate of 0.7 to 3.0 kg/ha.

3. A method according to claim 1 or claim 2, wherein the compound of formula 1 is applied at a 15 rate of from 0.7 to 1.5 kg/ha.

4. A method according to any one of claims 1 to 3, wherein, in the compound of formula 11, X is -CH(CH3)-.

5. A method of any one of claims 1 to 3, wherein, in the compound of formula 11, X is -(CH,),-.

6. A method according to claim 4 or 5, wherein the compound of formula 11 is applied at a rate of 20 0.7 to 1.5 kg/ha.

7. A method according to claim 6, wherein the compound of formulall is applied at a rate of from 0.75 to 1.0 kg/ha.

-CH-.

8. A method according to any one of claims 1 to 3, wherein, in the compound of formula 11, X is

9. A method according to claim 8, wherein the compound of formula 11 is applied at a rate of from 0.7 to 1.5 kg/ha.

10. A method according to claim 4 or 5, wherein the weight ratio of the compound of formula 1 to the compound of formula 11 is in the range of 1:3 to 1.5A.

11. A method according to claim 8, wherein the weight ratio of the compound of formula 1 to the 30 compound of formula 11 is in the range of 1:2 to 2:11.

12. A method according to any preceding claim, wherein the crop is a winter wheat spring barley or winter barley crop.

13. A method according to any preceding claim, wherein the crop is sprayed with spray application liquor formed by addition of water to an aqueous suspension or wettable powder formulation containing the compounds of formulae 1 and It.

14. A method according to any preceding claim, wherein the treatment of the crop takes place when the crop is at a stage between the one leaf stage and the appearance of the second node.

15. A method according to any preceding claim, wherein the compound of formula 11 is in a salt or ester form non-phytotoxic to cereal crops.

16. A method according to claim 1, substantially as hereinbefore described.

17. A herbicidal composition comprising a compound of formula 1, stated in claim 1, and a compound of formula 11, stated in claim 1, to be used at the rates and in the crops stated in claim 1, the weight ratio of the compound of formula 1 to the compound of formula 11 being in the range of 1:4 to 3A.

18. A composition according to claim 17, wherein, in the compound of formula 11, X is -CH(CH3)-.

19. A composition according to claim 17, wherein, in the compound of formula 11, X is -CHI_.

20. A composition according to claim 17, wherein, in the compound of formula 11, X is -(CH,)j----.

2 1. A composition according to any one of claims 17 to 20 in the form of an aqueous suspension 50 or a wettable powder.

22. A herbicidal composition comprising a compound of formula 1, stated in claim 1, together with a compound of formula 11, stated in claim 1, in which X is -(CH2)3-

23. A composition according to any one of claims 17 to 24, wherein the compound of formula 11 is in a salt or ester form non-phtotoxic to cereal crops.

24. A composition according to claim 17 to 22, substantially as hereinbefore described.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980. Published by the Patent Office. 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

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