GB1591106A

GB1591106A - Pest control

Info

Publication number: GB1591106A
Application number: GB54051/76A
Authority: GB
Original assignee: Wellcome Foundation Ltd
Current assignee: Wellcome Foundation Ltd
Priority date: 1976-12-24
Filing date: 1976-12-24
Publication date: 1981-06-17
Also published as: CA1091148A; FR2374851B1; BR7708597A; IE772627L; KE3313A; IE46539B1; FR2374851A1; NZ186082A; ZA777608B; AU3201677A; AU512901B2; JPS5391131A

Description

(54) PEST CONTROL (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 concerns the new use of known compounds and formulations containing them.

Pests of the Order Acarina are a source of concern in animal husbandry as troublesome pests of many domestic animals. They transmit a variety of infectious diseases by biting the animals, and can cause loss of conditions, weight loss and decrease in milk yield.

aCyano3phenoxybenzyl2,2dimethyl3(2,2dibromovinyl)cyclopr0panet carboxylate, and its optical and geometric isomers, (hereinafter referred to as the compounds of formula (I)), are known to have insecticidal activity against a variety of insects including Musca domestica (see for example British Patent Specification No.

1,413,491 and 1,448,228).

Our co-pending Application No. 54050/76 (Serial No. 1591105) discloses and claims the use of compounds of formula (I) as repellents of insects of the Order Diptera.

The structural formula (I) is intended to cover all the geometric and optical isomers of the compound including (+)-cis-isomer, the (+)-trans-isomer, the (f)-trans-isomer, the (+)-cis-isomer and the (1)-cis-trans-isomer (the sterochemistry referring to that of the cyclopropane ring). Moreover the alcohol moiety of the ester of formula (I) may be selected from the (-)-isomer, the (+)-isomer and the (+)-isomer. The preferred isomer is (- )-a-cyano-3-phenoxybenzyl-( + )-cis-2,2-dimethyl.3-(2 ,2-dibromovinyl)cyclopropane-1carboxylate, (Decamethrin).

It has now been found that the compounds of formula (I) are very active against pests of the Order Acarina, and that this activity is greater than that which could have been foreseen from its known activity against insects.

The compounds of formula (I) are highly effective against strains of acarines which are susceptible to conventional organophosphorus acaricides as well as to those strains which are resistant to conventional organophosphorus acaracides such as Boophilus microplus and B. decoloratus (Koch). The compounds of formula (I) may therefore be used to control acarine ectoparasites of animals, including single host and multi-host ticks, particularly those of the genera Boophilus, Rhipicephalus, Amblyomma, Hyalomma, Ixodes, Haemaphysalis, Dermacentor, and Anocentor, and mites of veterinary importance for example, the sheep scab mite Psoroptes ovis, and other ectoparasites of the sub-Orders Ixodoidea, Trombidiformes and Sarcoptiformes. 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 compounds of formula (I) may be used for such purposes by application of the compounds themselves or in a diluted form in known fashion as a dip, spray, foam, dust, aqueous suspension, paste, gel, shampoo, grease, pressure-pack, impregnated article or pour-on formulation. Dip concentrates are not applied per se, but diluted with water and the animals immersed in a dipping bath containing the dip wash. Sprays may be applied by hand or by means of a spray race or arch. The animal may be saturated with the spray by means of high volume application or superficially coated with the spray by means of light or ultra low volume application. Aqueous suspensions may be applied to the animal in the same manner as sprays. Dusts may be distributed over the animals by means of a powder applicator or incorporated in perforated bags attached to trees or rubbing bars. Pastes, 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 to the backs of animals such that all or most of the liquid is retained on the animals.

The compounds of formula (I) may be formulated 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 compound of formula (I) in intimate admixture with one or more carriers or diluents. The carriers may be liquid, solid or gaseous or comprise mixtures of such substances, and the compound of formula (I) may be present in a concentration of from 0.025 to 99% w/v depending upon whether the formulation requires further dilution.

Dusts may be prepared by intimate admixture of the chosen compound with a powdered solid inert carrier for example suitable clays, kaolin, talc, mica, starch and diatomaceous earths.

Sprays of a compound of formula (I) 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) which may also be used for dipping purposes. The concentrate preferably comprises a mixture of the active ingredient, with or without an organic solvent and one or more emulsifiers. Solvents may be present in wide limits but preferably in an amount of from 20 to 60% w/v of the composition and 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 but preferably in the range of 5 to 25% w/v and are conveniently non-ionic surface active agents including polyoxyalkylene esters of alkyl phenols and polyoxyethylene derivatives of hexitol anhydrides.

Dip washes may be prepared not only from emulsifiable concentrates but also from wettable powders comprising a compound of formula (I) in intimate admixture with a dispersing agent and one or more surface active agents.

Aqueous suspensions of a compound of formula (I) may comprise a suspension in water together with suspending, stabilizing or other agents. The suspensions may be applied per se or in a diluted form in known fashion.

Greases (or ointments) may be prepared from vegetable oils, synthetic esters of fatty acids or wool fat together with an inert base such as soft paraffin. A compound of formula (I) 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 and shampoos are also semi-solid preparations in which a compound of formula (I) 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, shampoos and pastes are usually applied without further dilution they should contain the appropriate percentage of the compound of formula (I) required for treatment.

Aerosol sprays may be prepared as a simple solution of the active ingredient 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 or suspension of a compound of formula (I) in a liquid medium which also contains a viscous oil to minimise spreading of the formulation on the surface of the animals.

An avian or mammal host may also be protected against infestation of Acarine ectoparasites by means of carrying a suitably-moulded, shaped plastic article impregnated with a compound of formula (I). Such articles include impregnated collars, tags, bands, sheets and strips suitably attached to appropriate parts of the body.

The concentration of the compound of formula (I) to be applied to an animal will vary according to the isomer chosen, the interval between treatments, the nature of the formulation and the likely infestation, but in general 0.001 to 0.1% w/v of the compound should be present in the applied formulation. The amount of the compound deposited on an animal will vary according to the method of application, size of the animal, concentration of the compound in the applied formulation and the nature of the formulation.

Dusts, greases, pastes and aerosol formulations are usually applied in a random fashion as described above and concentrations of 0.001 to 1.0% w/v of a compound of formula (I) in the applied formulation may be used.

The following Examples illustrate the present invention and the manner in which it may be carried out but should not be construed as in any way constituting a limitation thereof. In the Examples, compound Decamethrin refers to (-)-a-cyano-3-phenoxyberzyl-(+)-cis-2,2- dimethyl-3- (2 ,2-dibromovinyl)cyclopropane- 1-carboxylate.

EXAMPLE 1 Engorged female ticks of the Biarra strain of Boophilus microplus are immersed, in groups of 20 ticks per concentration, in a range of dilutions of a wash comprising Decamethrin in an organic solvent and emulsifiers emulsified in water. The desired range of concentrations for the test is obtained by further dilution of this master wash.

The ticks are removed from the wash after 10 minutes, dried, and stuck dorsal side 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.

IR90 = percentage concentration at which 90% inhibition of egg production occurs.

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

Decamethrin had an IR90(%) of 0.0019 and IR99(%) of 0.0039.

EXAMPLE 2 Wettable powder formulations (a) % w/w (b) % wiw Decamethrin 2.5 25.0 Celite (Trade Mark) 209 68.5 51.0 Kaolin 25.0 20.0 Perminal BX 1.0 1.0 Dispersol AC (Registered Trade Mark) 3.0 3.0 100.0 100.0 Celite 209 is an inert carrier.

Perminal BX and Dispersol AC are wetting agents.

EXAMPLE 3 Miscible-oil formulations (a) % w/w (b) % w/w Decamethrin 2.5 19.0 Cyclohexane - 15.0 Esso 200 Solvent 85.0 53.5 Anionic/Non-ionic Emulsifier 12.5 12.5 100.0 100.0 Esso 200 Solvent is a mobile oil which consists of 95% of aromatic hydrocarbons.

EXAMPLE 4 Dusting powder formulations (a) % w/w (b) % w/w Decamethrin 0.005 1.0 Talc 99.995 99.0 100.000 100.0 EXAMPLE 5 Aqueous suspensions (a) % w/w (b) % w/w Decamethrin 5.0 20.0 Aerosol OTB 0.2 0.2 Keltrol (Registered Trade Mark) 0.8 0.6 Water 74.0 64.2 Glycerol 20.0 15.0 100.0 100.0 Aerosol OTB is a wetting agent.

Keltrol is a thickening/suspending agent.

EXAMPLE 6 Pressure-packed aerosol formulations % w/w (a) (b) (c) (d) Decamethrin 0.20 0.10 0.05 0.01 Methylene chloride 25.0 44.90 39.95 Iso-propyl alcohol 14.80 - - 19.99 Refined Petroleum Solvent - 55.00 20.00 50/50 trichlorofluoro methane/ 60.00 - - dichlorodifluoro methane Butane/Propane mixture - - 40.00 Water - - - 40.00 Dimethyl ether - - - 40.00 100.00 100.00 100.00 100.00 The butane/propane mixture is chosen so as to have a pressure of 40 pounds per square inch at 21"C.

EXAMPLE 7 Larval ticks were tested for their susceptibility to Decamethrin by the Shaw Immersion technique. The immersion technique is described in the following references: Shaw R.D. (1966): Culture of an Organophosphorus-resistant strain of B. microplus (Can.) and an Assessment of its resistance spectrum, Bull. Ent. Res., 56, 389-405.

Shaw R.D. Cook M., Carson R.E. (1968): Development in the resistance status of the southern cattle-tick to organophosphorus and carbamate insecticides, J. Econ. Ent., 61, 1590-1594. The results are illustrated in Table 1.

TABLE 1 Activity of decamethrin against larval ticks Species Strain LC50 (%) LC99 (%) B. microplus Yeerongpilly CG 0.000027 0.00014 B. microplus Biarra 0.000058 0.00025 B. microplus Mackay 0.000063 0.00031 B. microplus Mt. Alford 0.00012 0.00037 B. decoloratus Berlin 0.000061 0.00030 R. evertsi Three Breezes < 0.0001 LC50 (%) is the percentage concentration of Decamethrin required to kill 50% of the larval ticks.

LC99 (%) is the percentage concentration of Decamethrin required to kill 99% of the larval ticks.

TABLE 2 A comparison of the activity of certain acaricides against larval and engorged female Biarra strain B. microplus ticks Larvae Engorged female LC50 LC99 IR90 IR99 Compound ppm ppm Pyrethrins 0.8 1.9 3000 8700 Allethrin 60.0 240.0 5300 10,000 Bioallethrin 12.0 72.0 4100 9800 Resmethrin 1.2 5.0 1400 2700 Bioresmethrin 1.4 5.6 4700 9500 Permethrin 0.7 2.1 620 1400 Cypermethrin 4.2 11.0 - Decamethrin 0.58 2.5 19 39 LC50 is the concentration required to kill 50% of the ticks.

LC99 is the concentration required to kill 99% of the ticks.

IR90 is the concentration at which 90% inhibition of egg-production occurs.

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

EXAMPLE 8 Two groups of five sheep infested with HCH resistant Psoroptes ovis were dipped once in a wash containing 0.005% w/v of Decamethrin. This treatment gave complete control against these pests throughout the duration of the fourteen week trial.

EXAMPLE 9 Calves carrying infestations of the Biarra strain of B. microplus were each hand-sprayed with eight litres of decamethrin at concentrations of either 0.001% or 0.0025% weight per volume using a motorised pump and lance (80-100 p.s.i.). The washes were prepared by appropriate dilution of a 20% weight per volume miscible-oil.

Observations, recording the number of engorged female ticks falling from the calves were made pre-treatment and then after treatment for the period of the trial.

Samples of engorged female ticks were incubated to monitor oviposition and larval hatch rate. Skin scrapes were made at intervals after treatment to determine effect. Larval tick infestations were continued for up to 14 days after treatment to determine the residual period of protection against reinfestation.

The results show that against a heavy infestation of ticks control was achieved at both 0.001% and 0.0025% weight per volume of decamethrin.

WHAT WE CLAIM IS: 1. A method of controlling infestations by pests of the Order Acarina of mammals and birds which comprises application to the mammal or bird of a non-toxic, infestation prevention or minimisation effective amount of a compound of formula

or of a formulation comprising said compound in intimate admixture with a carrier or diluent therefor.

2. A method according to claim 1 wherein the compound is (-)-a-cyano-3- phenoxybenzyl-( + )-cis-2,2-dimethyl-3-(2,2-dibromovinyl)c 3. A method according to claim 1 or 2 wherein the pest is of the sub-Order Ixodoidea.

4. A method according to claim 1 or 2 wherein the pest is of the sub-Order Sarcoptiformes.

5. A method according to claim 1 or 2 wherein the pest is of the sub-Order Trombidiformes.

6. A method according to any of claims 1 to 5 wherein the formulation is presented as a wettable dispersible powder.

7. A method according to any of claims 1 to 5 wherein the formulation is presented as an aqueous suspension.

8. A method according to any of claims 1 to 5 wherein the formulation is presented as a diluent free formulation.

9. A method according to any of claims 1 to 5 wherein the formulation is presented as a dusting powder.

10. A method according to any of claims 1 to 5 wherein the formulation is presented as a pressure-packed formulation.

11. A method according to any of claims 1 to 10 wherein the formulation comprises from 0.001% to 1% weight per volume of the active ingredient.

12. A method of controlling infestations by pests of the Order Acarina of mammals and birds which comprises application of a compound of formula:

or of a formulation comprising said compound substantially as hereinbefore defined with particular reference to Examples 1 to 10 inclusive.

13. A method according to any of claims 1 to 5 and 11 wherein the animal carries a plastic article impregnated with a compound of formula (I).

14. A method according to claim 13 wherein the article is a collar, tag, band, sheet or strip.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 0.001% and 0.0025% weight per volume of decamethrin. WHAT WE CLAIM IS:

1. A method of controlling infestations by pests of the Order Acarina of mammals and birds which comprises application to the mammal or bird of a non-toxic, infestation prevention or minimisation effective amount of a compound of formula

2. A method according to claim 1 wherein the compound is (-)-a-cyano-3- phenoxybenzyl-( + )-cis-2,2-dimethyl-3-(2,2-dibromovinyl)c

3. A method according to claim 1 or 2 wherein the pest is of the sub-Order Ixodoidea.