GB1602971A - Synergistic pesticidal compositions - Google Patents

Description

(54) SYNERGISTIC PESTICIDAL COMPOSITIONS (71) We, THE WELLCOME FOUNDATION LIMITED, of 183-193 Euston Road, London, N.W.1, a company incorporated in England do hereby declare that the invention for which we pray that a Patent may be granted to us and the method by which it is performed, to be particularly described in and by the following statement: This invention relates to novel potentiating compositions, their preparation, formulations containing them, the preparation of such formulations and to their use for the control of Arthropods.

Pyrethroids embraced by formula (I):

are known from U.K. Patent No. 1 413 491 to possess insecticidal activity, and are known from South African Patent No. 3211/1975 to possess acaricidal activity.

Pests of the Class Insecta and of the Order Acarina are troublesome to man, animal and plants. They are vectors of disease, and economic losses result from their depredations on plants and animals. Control of such pests over the years has come to depend strongly upon the use of chemical pesticides which can be naturally occuring compounds or synthetic organic chemicals.

Carbamate pesticides are used in both the agricultural and veterinary fields with varying degrees of success. Some of these substances are common to both fields whilst others have been solely employed in the agricultural field.

In recent years resistance to carbamate compounds has evolved in certain strains of Insects and Acarids both of agricultural and veterinary importance and accordingly the need for new, effective insecticides and acaricides has arisen.

It is known from Japanese Patent Publication No. 064 422/1975, that potentiation of activity occurs between a pyrethroid of formula (I) and certain carbamate compounds against Insects and Acarids of agricultural importance.

Employing such potentiating compositions, renders the use of pyrethroids of formula (I) more economic. The Japanese publication also suggests that the potentiation is due to the interaction between the inhibition of the enzyme acetylcholinesterase by the carbamate compound at the ganglionic junctions of the pest, which results in ganglionic nerve paralysis, and the disturbance of axonal nerve transmittance through the cell membranes of the nerve axons of the pest by the pyrethroid, which results in impaired axonal nerve transmission.

It has now been surprisingly found that there is potentiation between certain pyrethroids and certain carbamate compounds against pests of veterinary importance which are resistant to conventional carbamate compounds and which belong to the Phylum Arthropoda, in particular the Order Acarina. It is believed that the potentiation is due to the inhibition by the carbamate compound of certain esterases which degrade pyrethroids. The various rates at which different groups of arthropod pests, even within the same Order of classification, metabolise a pyrethroid makes it difficult to predict potentiation in one group of arthropod pests from a knowledge of potentiation in another group.

The pyrethroid ingredient for use in the present invention is of formula (III):

wherein Z and Z' are the same or different and each is halo such as fluoro, chloro or bromo; and X is hydrogen or cyano; provided that when both of Z and Z' are chloro X must be cyano.

Structural formula (III) is intended to encompass all the geometric and optical isomers. More particularly the acid moiety of the esters may be selected from the (+)-cis-isomer, the (+)-trans-isomer, the (+)-trans-isomer, the (+)-cis-isomer, and the (+)-cis-trans-isomer; the stereo-chemistry refers to that of the cyclopropane ring. Moreover when X is cyano the alcohol moiety of the ester may be selected from the (±isomer, the (-)-isomer or the (±isomer.

The preferred isomer of formula (III) is ()--cyano-3-phenoxybenzyl-(+)-cis- 2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropane- 1 -carboxylate. (Decamethrin).

The acaricidal activity of these esters is potentiated when used in combination with a pesticidal carbamate, especially one selected from l-naphthyl-N-methyl carbamate (carbaryl) and 3-methyl-5-isopropyl phenyl-N-(n-butanoyl)-N-methyl carbamate (promacyl). Other pesticidal carbamates (herein defined as those carbamates which have acaricidal activity) may however also be used.

The potentiating compositions of this invention are particularly effective against strains of acarines which are susceptible to conventional carbamate acaricides; against strains which are resistant to organophosphorus and carbamate ixodicides such as the cattle tick Boophilus microplus (Can.); and against strains which are resistant to pyrethroids. The compositions of this invention are particularly valuable in controlling acarine ectoparasites of animals, particularly those ticks of the genera Boophilus, Rhipicephalus: Amblyomma, Hyalomma, Ixodes, Haemaphisalls, Dermacentor and Anocentor, and mites of veterinary importance for example the sheep scab mite Psoroptes ovis. Such ectoparasites infest stock and domestic animals and fowls, depending upon the location of the host and the particular ectoparasite. Common hosts are cattle, pigs, sheep, goats, horses, camels, chickens, dogs and cats.

The compositions of this invention may be used for protecting the host against infestations of Acarids by application of the compositions themselves or in a diluted form in known fashion, as a dip, a spray, a dust, a paste, cream, gel, foam, shampoo or grease, a pressure-pack, an impregnated article, or a pour-on formulation. Dips are not applied per se, but the animals are immersed in a dipping bath containing the dip wash. Sprays may be applied by hand or by means of a spray race or arch or automatic treadle. Dusts may be distributed over the animals by hand application from suitable containers or incorporated in perforated bags attached to trees or rubbing bars. Pastes, foams, creams, gels, shampoos and greases may be applied manually or distributed over the surface of an inert material against which animals rub and transfer the material to their skins. Pour on formulations are dispensed as a unit of liquid of small volume on the backs of animals such that all or most of the liquid is retained on the animals.

The compositions may be presented either as formulations ready for use on the animals or as formulations requiring further dilution prior to application, but both types of formulations comprise a pyrethroid as defined above in combination with at least one carbamate compound as defined above in intimate admixture with one or more carriers or diluents. The carriers may be gaseous or solid or liquid or comprise mixtures of such substances and may be selected from one or more of the following: a solvent, an inert carrier, wetting, stabilising, emulsifying, thickening, dispersing and surface-active agents.

Dusts may be prepared by intimate admixture of the chosen compound with a powdered solid inert carrier for example suitable clays, kaolin, talcs, powdered chalk, calcium carbonate, Fuller's Earth, gypsum, diatomaceous earths and vegetable carriers.

Sprays of a composition of this invention may comprise a solution in an organic solvent (e.g. those listed below) or an emulsion in water (dip wash or spray wash) prepared in the field from an emulsifiable concentrate (otherwise known as a water miscible oil) or a water dispersible powder which may also be used for dipping purposes. The concentrate preferably comprises a mixture of the active ingredients, with or without an organic solvent and one or more emulsifiers.

Solvents may be selected from kerosene, ketones, alkanols, xylene, aromatic naphtha, and other solvents known in the formulating art. The concentration of emulsifiers may be varied within wide limits and are conveniently non-ionic or a mixture of non-ionic and anionic surfactants. The non-ionic surfactants will include polyoxyalkylene ethers of alkyl phenols or of alcohols. The anionic compounds include salts of alkylaryl sulphonic acids.

Dip washes may be prepared not only from emulsifiable concentrates but also from wettable powders comprising a composition of this invention in intimate admixture with an inert carrier and one or more surface active agents, and possibly a stabiliser and/or an antioxidant.

Greases may be prepared from vegetable oils, synthetic esters or fatty acids or wool fat together with an inert base such as soft paraffin. A composition of this invention is preferably distributed uniformly through the mixture in solution or suspension. Greases may also be made from emulsifiable concentrates by diluting them with an ointment base.

Pastes are also semi-solid preparations in which a composition of this invention may be present as an uniform dispersion in a suitable base such as soft or liquid paraffin or made on a non-greasy basis with glycerin, mucilage or a suitable soap. As greases and pastes are usually applied without further dilution they should contain the appropriate percentage of the composition required for treatment.

Aerosol sprays may be prepared as a simple solution of the active ingredients in the aerosol propellant and a co-solvent such as halogenated alkanes and the solvents referred to above, respectively. Pour-on formulations may be made as a solution, emulsion or suspension of a composition of this invention in a liquid medium which is of a viscosity such as to minimise loss of the formulation by run off from the surface of the animals. The pour-on formulations may be applied by a drenching gun, syringe or ladle or any other method known in the art.

A composition of the present invention preferably contains (5-950/,) weight by weight of a pyrethroid of formula (III) and between (5-95%) weight by weight of a carbamate defined hereinabove. The concentration of active ingredients present in a formulation applied to the pests or to their environment may be in the range of (0.0001-20%) by weight per unit volume of formulation.

The following Examples are provided by way of an illustration of the present invention and should not be construed as in any way constituting a limitation thereof.

Example 1.

Engorged female ticks of the Biarra strain or Boophilus microplus are immersed, in groups of 20 ticks per concentration, in a range of dilutions of the carbamate in combination with (-)-o-cyano-3-phenoxybenzyl-(+)ds-2,2-dimethyl-3- (2,2-dibromovin i) cyclopropane-l-carboxylate (hereinafter referred to as Decamethrin) at different ratios of carbamate to Decamethrin.

The composite wash is prepared immediately prior to the test by dilution (with water) of the two constituents. The constituents may be in the form of miscible oil or wettable powder formulations. The desired range of concentrations for the test is obtained by further dilution of this master solution or wash.

The ticks are removed from the wash after 10 minutes, dried, and stuck dorsalside down on double-sided adhesive tape. They remain in this position for 14 days when the numbers laying viable eggs are determined. From this data a regression line is plotted (concentration against % inhibition of egg-production) and the IR90 and IR99 values determined (Table 1). lR9O = concentration at which 90% inhibition of egg-production occurs.

IR99 = concentration at which 99% inhibition of egg-production occurs.

The values so obtained for the composite wash are compared with similar values obtained from the constituents of the composite wash when used alone. By reference to the equation for the harmonic mean, the factor of potentiation is determined (Table 2).

The equation for the harmonic mean is: X = Proportion of A + Proportion of B Proportion of A + Proportion of B IR90 A IR90 B X Y = IR90 mixture of A and B Y x Proportion of A Factor of Potentiation (FOP) = Proportion of A + B The FOP figures for the IR99 values were calculated in the same way.

Example 2.

Wettable Powder Formulations (a) Decamethrin 25.0 parts by weight Carbaryl 5.0 parts by weight Celite Grade 209 64.5 parts by weight Bevaloid 35/2 5.0 parts by weight Dispersol BX 0.5 parts by weight 100.0 Celite Grade 209 is a fine, purified grade of diatomaceous earth supplied by Johns Manville. "Celite" and "Dispersol" are registered Trade Marks.

Bevaloid 35/2 is a dispersing agent and is a condensation product of formaldehyde and sodium naphthalene sulphonate. It is supplied by Bevaloid Limited.

Dispersol BX is a wetting agent and is sodium alkylnaphthalene sulphonate. It supplied by ICI Limited.

Parts by weight (b) Decamethrin 10.0 16.7 3.3 Promacyl 10.0 3.3 16.7 Celite Grade 209 74.5 74.5 74.5 Bevaloid 35/2 5.0 5.0 5.0 Dispersol BX 0.5 0.5 0.5 100.0 100.0 100.0 Celite Grade 209 is a fine, purified grade of diatomaceous earth supplied by Johns Manville.

Bevaloid 35/2 is a dispersing agent and is a condensation product of formaldehyde and sodium naphthalene sulphonate. It is supplied by Bevaloid Ltd.

Dispersol BX is a wetting agent and is sodium alkyl naphthalene sulphonate. It is supplied by ICI Ltd.

Example 3.

Miscible Oil Formulations Parts by weight Decamethrin 5.0 5.0 2.0 Promacyl 5.0 1.0 10.0 Esso Solvent 200 70.0 74.0 68.0 Ethylan KEO 20.0 20.0 20.0 100.0 100.0 100.0 Ethylan KEO is an emulsifying agent which is nonyl phenol ethoxylate supplied by Lankro Chemicals Ltd.

Esso Solvent 200 is a mobile oil which consists of 95% of aromatic hydrocarbons.

"Ethylan" is a registered Trade Mark.

Example 4.

Dusting Powder Parts by weight Decamethrin 1.7 1.0 0.3 Promacyl 0.3 1.0 1.7 Talc 98.0 98.0 98.0 100.0 100.0 100.0 Example 5.

Aqueous Suspensions Parts by weight Decamethrin 15.0 9.0 3.0 Promacyl 3.0 9.0 15.0 Sodium dioctylsulphosuccinate 0.2 0.2 0.2 Xanthan Gum 0.4 0.4 0.4 Water 81.4 81.4 81.4 100.0 100.0 100.0 Example 6.

Pour-on Formulations Parts by weight Decamethrin 11.0 6.5 2.2 Promacyl 2.2 6.5 11.0 Cyclohexanone 24.7 24.7 24.7 Aromasol H 47.1 47.1 47.1 Corn Oil 15.0 15.0 15.0 100.0 100.0 100.0 Aromasol H is a mixture of aromatic hydrocarbons supplied by ICI Limited.

"Aromasol" is a registered Trade Mark.

TABLE 1 IR90/99 Values for the Carbamates alone and Compositions of these with Decamethrin at Various Ratios

DECAMETHRIN IXODICIDE COMPOSITE ALONE RATIO 1:1 WITH IR90 IR99 IR90 IR99 Carbaryl > 1.0 - 0.00034 0.00076 Promacyl 0.34 > 1.0 0.00033 0.00054 Decamethrin 0.0019 0.0039 Key:- Ratio Carbamate/Decamethrin TABLE 2 Factors of Potentiation of Composites of certain Carbamates and Decamethrin

DECAMETHRIN COMPOSITE RATIO 1:1 WITH IR90 IR99 Carbaryl > 5.6 Promacyl 5.8 7.2

Claims (1)

1. Key:- Ratio Carbamate/Decamethrin WHAT WE CLAIM IS:

   1. A pesticidal composition comprising a pyrethroid of formula

   wherein Z and Z1 are the same or different and each is halo, and X is hydrogen or cyano; provided that when Z or Z' are both chloro X must be cyano, together with at least one pesticidal carbamate compound as herein defined,

   2. A composition according to claim 1 wherein Z and Z' are the same and each is bromo.

   3. A composition according to claim 1 or 2 wherein the pyrethroid is (-)-a- cyano-3-phenoxybenzyl-(+)-cis.2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropane- 1 carboxylate.

   4. A composition according to any of claims 1 to 3 wherein the carbamate is carbaryl or promacyl.

   5. A composition according to any of claims 1 to 4 comprising from 5% to 950/, by weight of a pyrethroid together with from 5% to 95% by weight of a carbamate.

   6. A process for preparing a composition as defined in any of claims 1 to 5 which comprises bringing the pyrethroid into association with at least one of the carbamate compounds.

   7. A process according to claim 6 which comprises bringing (-)-cyano-3- phenoxybenzyl - (+) - cis -2,2- dimethyl - 3 - (2,2 - dibromovinyl)cyclopropane - I - carboxylate into association with promacyl or carbaryl.

   8. A formulation comprising a composition as defined in any of claims 1 to 5 in admixture with a carrier or diluent therefor.

   9. A formulation as claimed in claim 8 wherein the carrier is a solid or a liquid.

   10. A formulation as claimed in claim 8 or 9 in the form of an aqueous suspension, water miscible-oil, wettable dispersible powder, dusting-powder, pressure-packed formulation, or solution. í 1. A formulation as claimed in any of claims 8 to 10 comprising from 0.0001% to 20 ó by weight of active ingredients per unit volume of formulation.

   12. A process for preparing a formulation as defined in any of claims 8 to 11 which comprises bringing the said composition into association with the carrier or diluent therefor.

   13. A method for controlling veterinary ectoparasites of the Phylum Arthropoda of mammals or birds which comprises the application of a parasiticidally effective amount of a composition as defined in claim 1 to the ectoparasite or its enviroment.

   14. A method according to claim 13 for the control of veterinary ectoparasites of the Order Acarina.

   15. A method according to claim 13 or 14 wherein the pyrethroid is (-)-a- cyano-3-phenoxybenzyl-(+)-cis-2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropane- 1 - carboxylate.

   16. A method according to any of claims 13 to 15 wherein the pest is of the sub Order Ixodidae or Sarcoptiformes.

   17. A method according to any of claims 13 to 16 wherein the pest is of the family Ixodidae.

   18. A method according to any of claims 13 to 17 wherein a formulation comprising said composition in intimate admixture with a carrier or diluent is applied.

   19. A method according to claim 18 wherein one applies from 0.0001% to 20% by weight of active ingredients per unit volume of formulation.

   20. A pesticidal formulation as defined in claim 1 substantially as hereinbefore described with particular reference to Examples 2 to 6.

   21. A method for controlling veterinary ectoparasites as defined in claim 13 substantially as hereinbefore described with particular reference to Example 1.