GB2033749A - Method and composition for combating pests - Google Patents

Abstract

Pests, particularly arthropods, are combated by a combination of bendiocarb (2,2-dimethyl-1,3-benzodioxol- vinyl-N-methyl carbamate) and pirimicarb, (2-dimethylamino- 5,6-dimethyl-4-pyrimidinyl dimethyl carbamate or a salt thereof).

Description

SPECIFICATION Method and composition for combating pests Case 2746 The present invention relates to a method of combating pests, pesticidal compositions and their preparation.

The invention provides a method of combating pests at a locus infested or liable to be infested with them, which method comprises applying to the locus: (A) bendiocarb; and (B) pirimicarb In addition, the invention provides a pesticidal composition comprising (A) and (B).

(A) and (B) are known pesticides. Bendiocarb is 2,2-dimethyl-1 ,3-benzodioxol-4-yl N-methylcarbamate. Pirimicarb is 2-(dimethylamino)-5, 6-dimethyl-4-pyrimidinyl dimethylcarbamate or a salt, e.g. hydrogen oxalate or Rtoluenesulphonate, thereof. Usually, it is the base itself.

The present combination of pesticides is unexpectedly advantageous. Components (A) and (B) are synergistic, being surprisingly effective. The present method and composition achieve a greater pesticidal effect, e.g. against pests which attack crops above or below ground, than the additive effect of the essential components. They are particularly useful against pests of crops.

The proportions of (A) to (B) can vary over a wide range depending on such factors as the particular locus to be treated, the particular pests to be combated and the particular effect desired. Overall, however, the proportions of (A) to (B) may be for example from 1:20 to 5:1 respectively. Usually there is a greater weight of (B) than of (A). Preferably the proportions of (A) to (B) are 1:1-2.5 respectively. Parts, proportions and percentages in this specification are by weight unless otherwise indicated.

The essential components (A) and (B) can be applied together in a composition comprising (A) and (B). The compositions can be prepared by admixing the ingredients. The compositions may initially be produced in the form of concentrates, e.g. containing 0.5-85% in toto of the essential components (A) and (B), and these may be diluted with water or a hydrocarbon, usually water, at the point of use for application by spraying, generally such that the concentration in totoof (A) and (B) is 0.02-3%, e.g. 0.1-3%, preferably 0.15-2%. In a preferred embodiment, however, the compositions are produced directly for application, e.g. in the form of dusts or granules. A preferred composition is in the form of granules containing 0.75-3% (A) and 1.25-10% (B), e.g. 1.5% (A) and 2.5% (B).

Thus, overall the present compositions may contain for example 0.02-85% in toto of (A) and (B).

The compositions normally contain a carrier and/or a surface active agent.

The carrier may be a liquid, e.g. water (e.g. water used to dilute a concentrate for application). An organic solvent may be present with the water though this is not usually employed.

The carrier may be a liquid other than water, for example an organic solvent, e.g. a waterimmiscible solvent, for instance a hydrocarbon which boils within the range 130-270"C, in which the essential components are dissolved or suspended. A concentrate containing an organic solvent may contain a surface active agent so that the concentrate acts as a selfemulsifiable concentrate on admixture with water.

The carrier may be a solid, which may be finely divided. Examples of suitable solids are limestone, clays, sand, mica, chalk, attapulgite, diatomite, perlite, sepiolite, silicas, silicates, lignosulphonates and solid fertilizers. The carrier can be of natural or synthetic origin or can be a modified natural material.

Wettable powders soluble or dispersible in water may be formed by admixing the essential components with or without a carrier with a surface active agent. Preferably, however, the essential components are admixed with a solid carrier to form a dust, powder or granular product. In a preferred technique, granules containing (A) and (B) are prepared by (a) dissolving (A) and (B) in a volatile solvent to produce a solution containing 10-30% in toto by weight of (A) and (B), spraying the solution on to absorbent granules and evaporating off the solvent from the granules to constant weight of the granules, to form granules impregnated throughout with a mixture of (A) and (B), which granules contain 5-15% in toto by weight of (A) and (B), or (b) charging non-absorbent granules into a revolving, flighted, drum, and then charging into the drum in sequence, allowing time between each addition, (i) sticker, (ii) (A) and (B), singly or together, and (iii) absorbent dust to prevent the granules adhering to each other and to facilitate passage through application equipment, and then screening to remove oversize material, to form granules coated with a mixture of (A) and (B), which granules contain at most 10% in toto by weight of (A) and (B).

The term 'surface active agent' is used in the broad sense to include materials variously called emulsifying agents, dispersing agents and wetting agents. Such agents are well known in the pesticide art.

The surface active agents used may comprise anionic surface active agents, for example soaps, fatty sulphate esters such as dodecyl sodium sulphate, octadecyl sodium sulphate and cetyl sodium sulphate, fatty aromatic sulphonates such as alkyl-benzene sulphonates or butylnaphthalene sulphonates, more complex fatty sulphonates such as the amide condensation product of oleic acid and N-methyl taurine or the sodium sulphonate of dioctyl succinate.

The surface active agents may also comprise non-ionic agents, for example condensation products of fatty acids, fatty alcohols or fatty substituted phenols with ethylene oxide, or fatty esters and ethers of sugars or polyhydric alcohols, or the products obtained from the latter by condensation with ethylene oxide, or the products known as block copolymers of ethylene oxide and propylene oxide.

The surface active agents may also comprise cationic agents, for example cetyl trimethylammonium bromide.

Preferred surface active agents include fatty alkyl sulphates, alkyl aryl sulphonates, fatty alkyl ethoxylates, sulphated fatty alkyl ethoxylates, dialkyl sulphosuccinate esters, the amide condensation product of sleic acid and N-methyl taurine, lignin sulphonate salts, sulphonated naphthalene-formaldehyde condensates and sulphonated urea-formaldehyde condensates.

The compositions can contain a coating of an adhesive agent, e.g. a cellulose ether, and this can prolong the residual activity by forming a coating, thus inhibiting the physical removal of the active ingredients e.g. by wind, rain or rubbing.

Instead of applying (A) and (B) together in a composition such as is discussed above, they can be applied separately in analogous compositions containing just (A) or (B), particularly as whole or part of a chemical pesticide programme in a crop season. In a preferred sequence, (A) is applied at or immediately before planting a crop and (B) is applied after emergence of the crop.

Both simultaneous and sequential application may be employed, e.g. a mixture of (A) and (B) applied at or immediately before planting a crop and (B) applied after emergence of the crop.

Preferably a mixture of (A) and (B) is applied.

(A) and (B) may be mixed immediately before use. Desirably, however, they would already have been mixed.

The invention provides a one pack presentation, in which (A) and (B) are already mixed, and also a single package designed to hold (A) and (B), e.g. in the form of compositions such as are discussed above, in separate containers, for conjoint use e.g. by mixing of (A) and (B), e.g. inis spray tank, for application.

A further pesticide can be used in sequence or admixture with component (A) or (B). For instance, (A) and (B) can be applied separately and a further pesticide applied with (A).

Alternatively, a composition comprising a mixture of (A), (B) and the further pesticide can be applied. Usually the proportions of (A) to the further pesticide are from 1:1 0 to 20:1 e.g. from 1:10 to 10:1. The further pesticide can be an insecticide or acaricide, e.g. thiofanox, 3,3 dimethyl-1-(methylthio)-2-butanone O-[(methyl-amino)carbonyljoxime. It can also be amolluscicide, e.g. methiocarb (3,5-dimethyl-4-methylthiophenyl methylcarbamate) or metaldehyde, or a nematicide, e.g. fenamiphos (ethyl 3-methyl-4-(methylthio)phenyl 1 -methylethylphosphorami- date) aldicarb (2-methyl-2-(methylthio)propylideneaminomethylcarbamate) or oxamyl (S-methyl N', N'-dimethyl-N-(methylcarbamoyloxy)- 1 -thio-oximidate). The further pesticide is usually an acaricide, molluscicide or nematicide.

Fertilizers can be employed with the present essential pesticides.

Plants, the soil, land or aquatic or other areas can be treated by the present method.

Preferably it is conducted outdoors or in greenhouses.

The present method and composition can be applied against a wide range of pests. They are of particular interest against insect pests. The pest animals are usually arthropods, particularly insects or acarids, especially insects. The method and composition are particularly useful against pests of crops (i.e. desired plants), which can be horticultural crops but are preferably agricultural crops, e.g. potatoes, maize, sugar beet, cotton, rice, wheat, citrus crops, sugar cane, brassica crops or tobacco, especially maize or sugar beet. Thus, the method and composition are preferably applied to a locus at which a crop is growing or is to grow. Preferably, the mixture of essential pesticides, or one of them where the other is applied later, is applied at or immediately before planting; it may be incorporated in the soil immediately before planting. Preferably both (A) and (B) are soil applied, when (A) dramatically enhances the effect of (B).

The method and composition are useful against soil borne pests of desired plants, such as wireworms of the genus Agriotes, pygmy beetle Atomaria linearis, millipedes, Symphylans, Collembola and cutworms e.g. Agrotis spp. They are also useful against pests which attack desired plants above ground, such as mangold fly (Pegomyia betae), aphids e.g. Myzus persicae and Aphis fabae, leaf hoppers, e.g. rice leaf hoppers, scale insects and mealy bugs.

The present method is especially employed at such rates that 1-2, preferably 4-1-, kg in toto of (A) and (B) is applied per hectare. Preferably 200-3609 e.g. 3009 of (A) are applied per hectare, and preferably 400-1000g e.g. 500g of (B) are applied per hectare.

The invention is illustrated by the following Examples.

Example 1 Granules containing 1.5% bendiocarb and 3.75% pirimicarb (as the base itself) were applied at a rate of 300g of bendiocarb and 750g of pirimicarb per hectare, with sugar beet seed in the furrow at the time of drilling, using a Horstine Farmery Granule Applicator. Analogous plots were treated analogously with granules containing 5% pirimicarb, at a rate of 750g of pirimicarb per hectare, or with granules containing 5% bendiocarb, at a rate of 300g of bendiocarb per hectare. Analogous plots were not chemically treated, and were used as controls.

7 weeks after application, the number of blackfly colonies per 10 plants was counted. 4 replicates were carried out for each treatment.

The results were as follows: Rate, g per hectare Number of Blackfly Colonies Bendiocarb Pirimicarb per 10 Plants 300 0 74.5 0 750 13.8 3OQ 750 5.5 O 0 82.0 9 Example 2 Following the general procedure of Example 1, granules containing 1.5% bendiocarb and 2.5% pirimicarb (as the base itself) were applied at a rate of 300g of bendiocarb and 500g of piriiinicarb per hectare, with sugar beet seed. Analogous plots were treated with granules containing 5% pirimicarb, at a rate of 500g of pirimicarb per hectare, or with granules containing 5% bendiocarb, at a rate of 300g of bendiocarb per hectare.

The results were as follows: Rate, g per hectare Number of Blackfly Colonies Bendiocarb Pirimicarb per 10 Plants 300 0 73.5 0 500 29.8 300 500 16.3 0 0 86.3

Claims (16)

1. A method of combating pests at a locus infested or liable to be infested with them, which method comprises applying to the locus: (A) 2, 2-dimethyl- 1 , 3-benzodioxol-4-yl N-methylcarbamate; and (B) 2-(dimethylamino)-5, 6-dimethyl-4-pyrimidinyl dimethylcarbamate or a salt thereof.

2. A method according to claim 1 wherein (B) is 2-(dimethylamino)-5,6-dimethyl-4-pyrimidinyl dimethylcarbamate itself.

3. A method according to claim 1 or 2 wherein a mixture of (A) and (B) is applied.

4. A method according to any one of the preceding claims wherein a crop is growing at the locus.

5. A method according to any one of claims 1-3 wherein a crop is to grow at the locus.

6. A method according to claim 4 or 5 wherein the crop is maize or sugar beet.

7. A method according to any one of the preceding claims wherein the weight proportions of (A) to (B) are from 1:20 to 5:1.

8. A method according to claim 1 performed substantially as herein before described.

9. A method according to claim 1 performed substantially as herein before described in any one of the Examples.

10. A pesticidal composition comprising: (A) 2, 2-dimethyl- 1 , 3-benzoid ioxol-4-yl N-methylcarbamate; and (B) 2-(dimethylamino)-5, 6-dimethyl-4-pyrimidinyl dimethylcarbamate or a salt thereof.

11. A composition according to claim 10 wherein (B) is 2-(dimethylamino)-5,6-dimethyl-4- pyrimidinyl dimethylcarbamate itself.

1 2. A composition according to claim 10 or 11 wherein the weight proportions of (A) to (B) are from 1:20 to 5:1.

1 3. A composition according to claim 10 substantially as hereinbefore described.

14. A composition according to claim 10 substantially as hereinbefore described in any one of the Examples.

1 5. A process for preparing a composition claimed in any one of claims 10-14, which process comprises admixing the ingredients.

16. A composition claimed in any one of claims 10-15 prepared by a process claimed in claim 15.