GB2126897A

GB2126897A - Herbicidal compositions

Info

Publication number: GB2126897A
Application number: GB08324449A
Authority: GB
Inventors: Richard Newman
Original assignee: Pan Britannica Industries Ltd
Current assignee: Pan Britannica Industries Ltd
Priority date: 1982-09-20
Filing date: 1983-09-13
Publication date: 1984-04-04
Also published as: GB2126897B; GB8324449D0

Abstract

A herbicidal composition is disclosed comprising one or more hydroxybenzonitrile herbicidal compound and one or more dinitroaniline herbicidal compounds.

Description

SPECIFICATION Herbicidal compositions This invention relates to herbicidal compositions comprising a combination of admixture of herbicidal compounds and to a method of controlling weeds, more particularly but not exclusively in cereals using such herbicidal compositions.

According to the present invention a herbicidal composition comprises one or more hydroxybenzonitrile herbicidal compound and one or more dinitroaniline herbicidal compound.

The or each hydroxybenzonitrile compound used may be halogen substituted and may for example be a compound of the formulae

Formula 1 or a compound of the formulae

Formula 2 The compound of formulae 1 will henceforth be referred to as ioxynil. The compound of formula 2 will henceforth be known as bromoxynil. loxynil and Bromoxynil are British Standard common names.

The compound of the present invention preferably comprises in addition to one or more dinitroaniline herbicidal compound a mixture of ioxynii and bromoxynil, preferably present in a ratio one to another of from 2 to 3 to 1 to 1 by weight.

The or each hydroxybenzonitrile material is preferably present in the form of a salt or ester which is non-phytotoxic to cereals. As examples of the salts used are alkali metal, e.g. sodium or potassium, metal salts. An example of the esters used is the octanoate.

The or each dinitroaniline compound present in the composition of the invention may be a compound of the general formula

Formula 3 or a compound of the formula

Formula 4 wherein R4 is halogen, halo-alkyl or alkyl having 1 to 4 carbon atoms; R is ethyl, n-propyl, n-butyl or allyl and R1, R2 and R3 are selected from methyl, ethyl, n-propyl, n-butyl or allyl or R and R1, R2 and R3 when taken together with the nitrogen atom to which they are attached, represent pyrrolidine or additionally R, and R3 together with said nitrogen atom represent piperidino.

As examples of dinitroaniline materials which may be used, either falling within the above formula 3 or 4 or otherwise are the following: NN-di-n-prnpyl-4-trifluornmethyl-2,6-dinitrnaniline (Trifluralin*) N-propyl, N-n-butyl-4-trifluoromethyl-2,6-dinitro aniline (Benfluralin*) NN-di-n-propyl-4-isopropyl-2,6-dinitroaniline (Isopropalin*) N-n-propyl, N-(Cyclopropylmethyl)-4-trifluoromethyl-2,6-dinitroaniline (Profluralin*) N-ethyl, N-(2-methyl-propene-2-yl)-4-trifluoromethyl-2,6dinitroaniline (Methalpropalin*) N-( 1 -ethyl-n-propyl)-3,4-methyl-2,6-dinitroaniline (Pendimethalin*) N-(2-chloroethyl), N-propyl-4-trifluoromethyl-2,6-dinitroaniline (Fluchloralin*) *British standard common names The preferred dinitroaniline compound is NN-di-n-propyl 4-trifluoromethyl-2,6-dinitroaniline, British standard common name Trifluralin.

In its most preferred form the herbicidal composition of the present invention comprises ioxynil, bromoxynil and trifluralin. In such a composition the oxynil and bromoxynil may be employed as the free phenol or as a salt or ester which is non-phytotoxic to cereals such as alkali metal e.g. sodium or potassium salt or an octanoate ester thereof. The ratio of ioxynil to bromoxynil is preferably in the range 2 to 3 to 1 to 1 by weight.

The weight ratio of hydroxybenzonitrile herbicidal compound or compounds to dinitroaniline herbicidal compound or compounds used in the compositions of the present invention is preferably in the ratio of 1:10 to 5:1 by weight.

The compositions of the present invention may comprise an emulsifiable concentrate or an aqueous suspension of both hydroxybenzonitrile(s) and dinitroaniline(s) for addition to water before use, or may comprise individual emulsifiable concentrates or aqueous suspensions of hydroxybenzonitrile(s) and dinitroaniline(s) for admixture and addition to water before use. The admixture may be hydroxybenzonitrile with dinitroaniline and then addition to water or addition of one to water and then the other.

In accordance with a further aspect of the invention a method of controlling weeds in cereals comprises application to the cereal of a composition as defined above. When a concentrate or concentrates are provided they will have been added to water prior to use as is conventional. As an example when the composition comprises ioxynil, bromoxynil and trifluralin, the ioxynil and bromoxynil may be present as octanoate esters and may be such as to enable application at a rate of 0.06 to 0.32 kg/ha, for example 0.1 6 to 0.32 kg/ha, ioxynil, and 0.12 to 0.64 kg/ha, for example, 0.24 to 0.48 kg/ha bromoxynil, the corresponding rate for the trifibralin being 0.24 to 0.96 kg/ha.

The use of hydroxybenzonitrile compounds as herbicides for use in the control of for example broad leaved weeds in cereals is wellknown, such use normally taking place in spring. Dinitroaniline compounds such a trifluralin have also been used for some time to control weeds in cereals but they have to date mainly been found effective when used as a pre-emergent application in the autumn.

Application of dinitroaniline herbicides in spring after crop emergence has in the past been found ineffective. By application of the composition of the present invention, for example of ioxynil, bromoxynil and trifluralin or equivalent chemical compounds in the spring after crop emergence it has now been found that better control of weeds can be obtained over the effect obtainable previously by use of hydroxybenzonitrile such as oxynil and/or bromoxynil and of course over the use of trifluralin or similar dinitroaniline herbicides which have as indicated above been found to be ineffective when used alone.

For the purposes of comparison with the rates of application set out above ioxynil and bromoxynil are normally applied together art a rate of 0.28 to 1.12 kg/ha and trifluralin or the like chemical equivalent compound at a rate of 0.96 to 1.2 kg/ha.

The application of the composition of the present invention is preferably carried out when the crop is between the start of tillering (Growth stage 2) and the appearance of the second node (Growth stage 7). The cereal crops to which compositions of the present invention may be applied with notable effect are wheat barley and oats but it is anticipated that others may also benefit to greater or lesser degrees.

The cereal growth stage key used in this specification is Feekes -- large scale of which can be found in "Plant Pathology 3 1954".

The hydroxybenzonitrile and dinitroanilines together comprising the herbicidal composition of the present invention should be applied together. They may be either mixed together as a single formulation which is diluted in water before application to the crop or supplied as a two-part formulation, the first part containing one or more hydroxybenzonitrile compound and the second part containing one or more dinitroaniline compound each in emulsifiable concentrate or aqueous suspension the two being diluted together in the appropriate volume of water before application. Mixture in either case may be in the spray tank of an agricultural machine prior to spraying.In both cases the total amount of herbicide composition applied shouid be in the range of 50 to 400 litres of water per acre, the higher rate being used for control of large over-wintered weeds in autumn sown crops or where crop cover is dense.

The compositions of the present invention may be formulated in various ways and some specific examples will now be described by way of example. The following examples all use the above mentioned materials loxynil, bromoxynil and trifluralin although it will be appreciated that simiiar or equivalent chemical compositions may be used within the scope of the present invention.

Concentrate formulations of ioxynil, bromoxynil and trifluralin may be prepared in the form known as an emulsifiable concentrate or as an aqueous suspension. Emulsifiable concentrates are produced by dissolving the active ingredient in one or more suitable solvents and adding emulsifiers as illustrated by the following composition.

% Weight/Volume loxynil octanoate 1-40 Bromoxynil octanoate 1-56 Trifluralin 1--48 Emulsifier(s) 2-12 Solvent(s) to 100 Aqueous suspensions have the active ingredient suspended in water together with surfactants, suspending agents, anti-freeze or preservative as illustrated by the following composition.

% Weight/Voiume loxynil octanoate 2-50 Bromoxynil octanoate 2-60 Trifluralin 1-60 Wetting agent 0-10 Dispersing agent 0-5 Suspending agent 0--5 Anti-freeze 0-10 Preservative 0-2 Water to 100 EXAMPLES 1-3 The following emulsifiable concentrates were prepared, % Weight/Volume 1. Bromoxynil octanoate 23 loxynil octanoate 14 Trifluralin 32 Alkali metal salt of an alkylaryl sulphonate 4 Alkyl phenyl ethoxylate 4 Xylene To 100 2. Bromoxynil octanoate 23 loxynil octanoate 14 Trifluralin 16 Alkali metal salt of an alkylaryl sulphonate 3 Alkyl phenyl ethoxylate 4 Xylene To 100 3.Bromoxynil octanoate 17.25 loxynil octanoate 10.50 Trifluralin 24.0 Amine salt of an alkylaryl sulphonate 4 Polyhydric alcohol fatty ester ethoxylate 4 Heavy aromatic naphtha To 100 EXAMPLES 4-6 The following aqueous suspensions were prepared: 4. loxynil octanoate 18 Bromoxynil octanoate 11 Trifluralin 25 Cellulose ether 0.3 Formaldehyde 0.1 Alkyl phenyl ethoxylate 0.5 Lignin sulphonate 3.0 Propylene glycol 3.0 Water To 100 5. loxynil octanoate 18 Bromoxynil octanoate 11 Trifluralin 12 Cellulose ether 0.4 Formaldehyde 0.1 Alkyl phenyl ethoxylate 0.5 Ethylene glycol 3.0 Water To 100 6. loxynil octanoate 18 Bromoxynil octanoate 11 Trifluralin 18 Bentonite clay 1 Amine ethoxylate 0.5 Propylene glycol 3 Water To 100 EXAMPLE 7 Several field trials were carried out on Spring Barley.Applications were made as tank mixes at a volume of 200 litre/hectare. The concentrates from which the sprays were formed were an emulsifiable concentrate containing 160 g/litre ioxynil and 240 g/litre bromoxynil as the octanoates and an emulsifiable concentrate containing 480 g/litre trifluralin. Application was made between start of tillering and the appearance of the second node. Weed control was assessed visually and results expressed as the percentage control of the individual weed species present.

% Control Dose rate Sow Chick Fat Herbicide kg /ha Charlock Bindweed thistle weed Horsetail Cleavers Hen Trifluralin 0.48 0 0 0 0 0 0 0 Trifluralin 0.96 0 0 0 0 0 0 0 loxynil 0.16 100 20 40 17 20 0 100 Bromoxynil 0.24 Ioxynil 0.16 Bromoxynil 0.24 100 30 50 60 50 30 100 Trifluralin 0.48 Thus it can be seen that the addition of trifluralin has given increased control of five of the seven weed species present. There was no damage to the crop.

EXAMPLE 8 To further illustrate the increase in weed control obtained by the addition of trifluralin to ioxynil and bromoxynil a trial was carried out in a field of Winter Wheat which had been sown in the previous October. The crop was sprayed in April at growth stage 2. The herbicide applied was a tank mix as in Example seven.

Only four weeds were present in sufficient numbers to give a reliable assessment.

% Control Dose rate Herbicide kg/ha Charlock Bindweed Sowthistle Cleavers Trifluralin 0.48 0 0 0 0 Trifluralin 0.96 0 0 0 0 Bromoxynil oo 264 100 - 0.24 loxynil 0.16 Bromoxynil 0.24 100 44 65 32 Trifluralin 0.48

Thus it will be seen in the above tables in relation to Exampies 7 and 8 that not only is increased herbicidal performance achieved by the compositions of the present invention in relation tosome of the weed species present, in some cases dramatically, the effect of the addition of trifluralin to oxynil and bromoxynil does not reduce the efficacy of ioxynil and bromoxynil. Thus the composition of the present invention not only provides improved efficacy in relation to certain weeds but also increases the applicability as against known herbicidal compositions.

EXAMPLE 9 As a still further illustration of the increase in weed control obtained by the addition of trifluralin to oxynil and bromoxynil a trial was carried out on Spring Barley at three different sites. The crops were sprayed on 14 May and weed control was assessed three weeks later.

The weeds present were:-- Black-bindweed, Redshank, Plantain, Common Field-Speedwell, Red Dead-nettle, Fat Hen, Knotgrass, Scarlet Pimpernel, Chickweed, Mayweed and Cleavers.

Treatment kg/ha % Weed Control loxynil Bromoxynil Trifluralin Site 1 Site 2 Site 3 Mean 133 200 0 50 68 73 64 133 200- 240 59 83 83 75 133 200 480- 73 94 93 87 133 200- 960 80 97 93 90 240 360 0 71 88 83 81 240- 360 240 79 96 87 87 240 360 480 86 98 90 91 240 360 960 95 99 100 98 0 0 960 0 0 0 0 It can be seen that trifluralin greatly improved the activity of each ioxynil/bromoxynil combination, even though there was no discernible weed control from trifluralin alone at the highest concentration used.

Claims

1. A herbicidal composition comprising one or more hydroxybenzonitrile herbicidal compound and one or more dinitroaniline herbicidal compound.

2. A herbicidal compound as claimed in Claim 1 wherein the or each hydroxybenzonitrile is halogen substituted.

3. A herbicidal compound as claimed in Claim 2 wherein the or each hydroxybenzonitrile is a compound of the formula

Formula 1 or a compound of the formula

Formula 2

4. A herbicidal compound as claimed in Claim 3 wherein the hydroxybenzonitrile herbicide comprises a mixture of compounds of formulae (1) and (2).

5. A herbicidal compound as claimed in Claim 4 wherein the compounds of formulae (1) and (2) are present in a ratio one to another of from about 2:3 to 1:1 by weight.

6. A herbicidal compound as claimed in any of the preceding claims wherein the or each hydroxybenzonitrile is present in the form of non-phytotoxic salts or esters.

7. A herbicidal compound as claimed in any of the preceding claims wherein the or each dinitroaniline is a compound of the general formula

Formula 3 or a compound of the formula

Formula 4 wherein R4 is halogen, halo-alkyl or alkyl having 1 to 4 carbon atoms; R is ethyl, n-propyl, n-butyl or allyl and R1, R2 and R3 are selected from methyl, ethyl, n-propyl, n-butyl or allyl or R and R1, R2 and R3, when taken together with the nitrogen atom to which they are attached, represent pyrrolidine or additionally R, and R3 together with said nitrogen atom represent piperidino.

8. A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is NN-di-npropyl 4-trifluoromethyl-2,6-dinitroaniline.

9. A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is N-propyl, N-n-butyl 4 trifluoromethyl-2,6-dinitroaniline.

10. A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is NN-di n-propyl-4-isopropyl-2,6-din itroaniline.

1 A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is N-npropyl N(Cyclopropylmethyl)-4-trifluoromethyl)-2,6-dinitroaniline.

1 2. A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is N-ethyl N-(2-methyi-propene-2-yl)-4-trifl uoromethyl-2,6-dinitroaniline.

13. A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is N-(1 ethyl-n-propyl)-3,4-methyl-2,6-dinitroaniline.

1 4. A herbicidal compound as claimed in any of Claims 1 to 6 wherein the dinitroaniline is N-(2chlorethyl) N-propyl-4-trifluoromethyl-2,6-dinitroaniline.

1 5. A herbicidal compound as claimed in any of the preceding claims wherein the hydroxybenzonitrile compound or compounds and the dinitroaniline compound or compounds are present in a ratio one to another of from 1:10 to 5:1 by weight.

16. A herbicidal compound as claimed in any of the preceding claims comprising an emulsifiable concentrate or aqueous suspension for addition to water before use.

1 7. A herbicidal compound as claimed in any of the preceding claims 1 to 1 5 comprising individual emulsifiable concentrates or aqueous suspensions of hydroxybenzonitrile(s) and dinitroaniline(s) for admixture and addition to water before use.

18. A herbicidal compound as claimed in Claim 1 comprising the compound of formula 1, the compound of formula 2 and N,N-di-n-propyl-4-trifluoromethyl-2,6-dinitroaniline.

19. A herbicidal compound as claimed in Claim 18 wherein the compounds of formulae 1 and 2 are present as their octanoate esters.

20. A herbicidal composition substantially as described herein with reference to any of the Examples hereto.

21. A method of controlling weeds in cereals comprising application to the cereal of a composition as claimed in any of the preceding claims.