IE52109B1 - A method of controlling keds,blow flies and mites on sheep - Google Patents

Description

The present invention relates to pour-on formulations for controlling keds, blow flies and mites on sheep. The invention has special application to the control of keds (Melophagus ovinus) particularly on merino sheep.

Traditionally, sheep have been treated for the control of ectoparasites by dipping or spraying the whole external surface of the sheep. However, this is an inconvenient and time-consuming operation. Attempts have been made to treat infested sheep, particularly lice-infested sheep, with a large variety of known insecticides by various more convenient routes, including pour-on treatments, subcutaneous injection, and by oral dosage. Hitherto, none of the treatments had any significant effect on the control of the lice populations. In particular, merino sheep which have very dense wool have not responded to such treatments.

Our copending Irish Applications Nos. 2719/31 and disclose and claim a method of controlling lice on sheep by localised administration of a pyrethroid and formulations of pyrethroids in a solvent system containing diethylene glycol mon-n15 butyl ether, respectively.

The present invention is based on the unexpected discovery that localised applications of-pyrethroids are surprisingly effective in controlling and eradicating keds, blow flies and mites. It is particularly surprising that such localised application is effective ever#on long-woolled merino sheep.

Thus, the present invention provides a method of controlling keds, mites and/or blowflies on which comprises the application onto a localised region of the skin or fleece of a sheep of a pyrethroid of the formula.

CH-O-M R. .5 X -253108 wherein M is CO - CH - CH s \ CH * C χ/ CT or CH, CH, - CO - CH CH zc\ CH · \ / CH, CO CH - R.

I CH, CH \ CH. and wherein to Χή are independently selected from halo, C^-C^ alkyl, halogen-substituted Cj-C^ alkyl, and halogen-substituted phenyl; Xj is -H or halo; R^ is -H or cyano; and Rj is halogen-substituted phenyl. -352109 By localised application is meant thet the pyrethroid Is only applied to a minor portion of the skin or fleece of the sheep, generally as a line or spot on the sheep’s back. It has been surprisingly discovered that, notwithstanding the presence of a sometimes dense coating of wool, the pyrethroid appears to act over the entire surface of the sheep. It is believed as a hypothesis that the pyrethroid is transmitted over the surface of the sheep by diffusion through the wool grease.

The pyrethroid is generally applied as a liquid formulation, a paste or as a solid powder. Surprisingly, it has been found that it is not necessary that the pyrethroid be dissolved to be effective.

The localised application is preferably carried out as a pour-on treatment by pouring the formulation comprising the pyrethroid along the back of the sheep (i.e. a so called backline application). Surprisingly, it is not necessary to totally immerse the sheep in the formulation so that the treatment of large numbers of sheep is facilitated.

Alternatively, the application may be carried out by means of a localised spray or aerosol, usually along the sheep's back as it passes through a sheep race. The aerosol might comprise the pyrethroid dissolved in a liquid carbon dioxide propellant.

Without wishing to be iimted by any theoretical mode of action, it is believed that the pyrethroid acts superficially and is not dermally and systemically absorbed. It is therefore surprising that protection over the entire sheep is attainable from a localised application.

The pyrethroid is preferably selected from the group of light stable pyrethroids. Deltamethrin (also knwon as decamethrin) is preferred and is a solid under norma! conditions. Suitable pyrethroids are disclosed in Tables I to III. -410 521UH Ci Ci Ci CH, CF, Ci CH, H CN cyhalo thnn F CN flumethrin F CN cyfluthrin H CN cyphenothrir, -552108 IABLL.1I .. ζΧχ M «= - CO - CH — - CH - CH - C \ z 1 x2 z C x32 CH3CH3 No. XjX2X3X4X5 R1 trivial name 9 Br Br Br Br H CN tralomethrin 10 Cl Cl Br Br H CN tralocythrin 53109 -6tt I* a particular advantage of the present method that only amall volume» of pyrethroid or pyrethruld-containing formula need to br applied. Depending on the size of the sheep, the volume applied will generally lie in the range 2 to 15 ml per sheep. For convenience, the pyrethroid will generally be applied In a liquid formulation.

Depending on the efficacy of the particular pyrethroid employed, the formulation generally contain» from 0.1 to 500, preferably 1 to 250 mg/ml of the pyrethroid. Moreover, the pyrethroid is preferably applied to the sheep in an application of from 1 to 500, preferably 1.5 to 250 mg/kg body weight.

The formulation may be applied to full-woolled or theared sheep. However, higher doses are required for full-woolled sheep.

The pyrethroid is preferably applied in the form of a pour-on formulation. The formulation may comprise one or more organic solvents, such as xylene, toluene, cyclohexanone, and a glycol. ] 5 One preferred solvent system comprises 30-70 wt % xylene, 20-40- wt % cyclohexanone and 5-25 wt % vegetable oil.

Suitable glycols include ethylene glycol and propylene glycol, polyethylene glycols and polypropylene glycols, ethylene glycol-propylene glycol copolymers, and alkyl ethers and alkyl ether esters of the general formula: R' 20 R2O - (CH--CHO) -CO-R3 n = C, alkyl or hydrogen, 1 = C^-Cj alkyl, hydrogen or -CO-R3, Rj = Cj-Cj2 alkyl, and n = 1 - 40 Diethylene glycol mono-n-butyl ether has been found to be particularly useful, tt has been found to have minimal adverse effect on the skin in terms of a mild epidermal shedding seen with other solvents in some sheep.

Alternatively, the formulation may be an aqueous formulation containing the pyrethroid -7ln the form of a suspension or emulsion and comprising suitable surfactants to stabilise the suspension or emulsion, and prevent undue run-off ffWn the back of the sheep. Thus, It has been surprisingly found that the pyrethroid Is effective even when In the undissolved state. Paraffin oils, vegetable oils, e.g. corn oil, peanut oil, castor oil, olive oil, can be added as viscosity modifiers and co-solvents.

Alkylamides and esters of fatty adds are useful formulation adjuncts e.g. n-butyl oleate, Ν,Ν-dimethyl oleamide and isoprqpyl myristate (IPM).

It has been found that the inctudion of an antioxidant such as 2,6-ditert-butyl-4cresol (BHT) or 2-tert-butyl-4-methoxyphenol (BHA) has a useful stabilising effect on the active ingredients in formulations based on glycols, glycol ethers, glycol ether esters and cyclohexanone..

The present invention will now be Illustrated with reference to comparative tests showing the lack of activity of a large umber of conventional insecticides, and with reference to specific examples illustrating the present invention.

(I) TREATMENT ACCORDING TO THE PRESENT INVENTION A variety of pyrethroids were evaluated in the control of keds on merino sheep, when applied by a liquid pour-on formulation.

The efficacy of deltamethrin against infestations of merino sheep with keds (Melophagus ovinus) was determined by applying B ml of deltamethrin in a . xylene (55 wt %), cyclohexanone (30 wt %), corn oil (15 wt %) solvent system as a backline treatment to twenty newly shorn sheep. Twenty further sheep were treated in the same way with deltamethrin in a diethylene glycol mono-n-butyl ether (DGBEXB5 wt %), isopropyl myristate (IPM)(15 wt %) 2,6ditert-butyl-4-cresol(BHTX2.5 g/l) given in Test 2. The concentration of deltamethrin was 10 g/1.

All forty sheep were re-examined 10 weeks after treatment and no live keds were found. (Π) FORMULATIONS FOR USE ACCORDING TO THE PRESENT INVENTION Suitable formulations are presented in the following Examples. In general, a suitable system contains 0 to 100% by weight xylene, 0 to 100% by weight cyclohexanone, and up to 20% by weight corn oil. -6Examplc 1 .1 ς of technic·) deltamethrin (989 g active per kg) wes dissolved In solvent consisting of: cyclohexanone Sudan Red IV (oil soluble dye) 50 ppm and the volume adjusted to one litre to give a solutio containing 10 g/l deltamethrin.

Example 2 g of technical deltamethrin (989 g active constituent per kg) was dissolved in a solvent blend containing: xylene cyclohexanone corn oil Sudan Red IV 55% by weight 30% by weight 15% by weight 100 ppm and the volume adjusted to one litre with the same solvent blend to give a solution ) 5 containing 50 g/1 deltamethrin.

Example 3 .1 g of technical deltamethrin (989 g active per kg) was dissolved in a solvent blend, containing: xylene cyclohexanone corn oil Sudan Red IV 55% by weight 30% by weight 15% by weight 50 ppm and the volume adjusted to one litre with the same solvent blend, to give a solution containing 10 g/l deltamethrin.

Example 4 g of technical deltamethrin (989 g active per kg) was dissolved in the same solvent blend given in Example 3 and the volume adjusted to give a solution containing 50 g/1 deltamethrin. -9Example 5 .1 g of technical deltamethrin (989 g active per kg) was dissolved In a solvent consisting of: diethylene glycol monbutyl ether BHT antioxidant 2500 ppm Sudan Red IV 50 ppm and the volume adjusted to one litre with the same solvent to give a solution containing 10 g/1 deltemethrin.

Example 6 .1 g of technical deltamethrin (989 g active per kg) was dissolved in a solvent blend containing: cyclohexanone 50% by weight diethylene glycol monobutyl ether 50% by weight BHT antioxidant 2500 ppm Solvent Blue No. 36 50 ppm and the volume adjusted with the same solvent blend to give s solution containing 10 g/I deltamethrin.

Example 7 .1 g of technical deltamethrin (989 g active kg) was dissolved in a variety of solvent blends containing: diethylene glycol monobutyl ether or 85-90% by weight ethylene glycol monobutyl ether acetate isopropyl myristate 10-15% by weight BHT antioxidant 2500 ppm Sudan Red IV 50 ppm 53108 and the volume adjusted with the respective solvent biend to give a solution containing 10 g/1 deltamethrin* Example 8 Amounts of 2.6, 10.5, 42.5 and 84.2 g of technical cypermethrin (950 g active per 5 kg) were dissolved in a solvent blend containing: Xylene 55% by weight cyclohexanone 30% by weight com oil 15% by weight and the volume adjusted to one litre with the same solvent blend to give ' solutions containing 2.5 g, 10 g, 40 g end 80 g per litre respectively of cypermethrin.

Example 9 103 g of technical permethrln (970 g active per kg) in which the cis:trans isomer (arising from the two asymmetric carbon atoms in the cyclopropane ring) ratio was :75 was dissolved in a solvent blend containing: xylene 55% by weight cyclohexanone 30% by weight corn oil 15% by weight and the volume adjusted to one litre with the same solvent blend to give a solution containing 100 g/1 permethrin.

Example 10 An aqueous suspension of deltamethrin was prepared by suspending 10.1 g of technical deltamethrin of average particle size 2 to 5 microns in an aqueous formulation containing: non-ionic wetting agent 1.5 g mole nonylphenol condensed with 15 moles of ethylene oxide S2109 -11fumed silicon dioxide 5.0 g xanthan gum A.O g propylene glycol 60.0 g formaldehyde 1.0 g silicone oil lantifoeming agent) 1.0 g water to one litre.

Various other deltamethrin suspensions in the range 1 to 500 g/1 deltamethrin were also prepared.

Claims (32)

1. A method of controlling Keds, mites and/or blowflies on sheep which comprises the application onto a localised region of the skin or fleece of a sheep of a pyrethroid of the formula. 5 wherein ch 3 ch 3 or CO - CH - R. I / C V CH, Cl and wherein Xj to are independently aelected from halo, C^-C^ alkyl, halogensubstituted Cj-C^ alky!, and halogen-substituted phenyl; 13Xj ts -H or halo; is -H or cyano; and R^ is halogen-substituted phenyl

2. A method according to claim 1 wherein the pyrethroid is selected from the group of light stable pyrethroids.

3. A method according to claim 1 or 2 wherein the pyrethroid is selected from permethrin, phenothrin, cyfluthrin, cyphenothrin, tralomethrin, tralocythrin and fenvalerate (all as herein defined).

4. A method according to claim 1 or 2 wherein the pyrethroid is cypermethrin (as 0 herein defined).

5. A method according to claim 1 or 2 wherein the pyrethroid is cyhalothrin (as herein defined).

6. A method according to claim 1 or 2 wherein the pyrethroid is flumethrin (as herein defined). )5

7. A method according to claim 1 or 2 wherein the pyrethroid is deltamethrin (as herein defined).

8. A method according to any preceding claim wherein the pyrethoid is applied to a sheared sheep.

9. A method according tc any of preceding claims J to 7 wherein the pyrethroid is 20 applied to a substantially full-woolled sheep.

10. A method according to any preceding claim wherein the sheep is a merino sheep.

11. A method according to any preceding claim wherein the pyrethroid is applied at a rate of from 1 to 500 mg per kilogram sheep body weight.

12. A method according to any preceding claim wherein a pour-on application is made 14of from 2 to 15 ml of a liquid formulation comprising the pyrethroid.

13. A method according to any preceding claim wherein from 2-15 mis of a liquid formulation is applied which comprises the pyrethroid dissolved in one or more organic solvents.

14. A method according to any preceding claim wherein a liquid formulation ii applied which comprises the pyrethroid and one or more of toluene, xylene and a glycol.

15. A-method according to any preceding claim wherein a liquid formulation is applied which comprises the pyrethroid in a solvent system containing a glycol.

16. A method according to clBim 15 wherein the glycol is selected from ethylene glycol, propylene glycol, polyethylene glycols, polypropylene glycols, and ethylene glycol - propylene glycol copolymers.

17. A method according to any one of claims 1 to 13 wherein a liquid formulation is applied which comprises -the pyrethroid in a solvent system containing an alkyl ether of a glycol. IB. A method according to claim 17 wherein the alkyl ether of the glycol is an alkyl ether of a glycol selected from ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycols and ethylene glycol - propylene glycol copolymers.

18. 19. A method according to any one of claims 1 to 13 wherein a liquid formulation is applied which comprises the pyrethroid in a solvent system containing a gl.co! alkyl ether ester of the general formula R' 2 I RO - (CH- - CHO)- CO - R z n wherein R^ = alkyl or hydrogen, = Cj-Cj alkyl,hydrogen or -CO-R\ Rj = C l* C 12 aIky1 ’ and n = 1-40 -1520. A method according to any one of claim* 1 to 12 wherein a liquid formulation i* applied which comprises a suspension or emulsion of the pyrethroid In an aqueous liquid.

19. 21. A method according to any one of claims 13 to 20 wherein the liquid formulation also contains a paraffin oil or vegetable oil.

20. 22. A method according to any one of claims 13 to 21 wherein the liquid formulation also contains an elkylamide or on ester of a fatty acid.

21. 23. A method according to any one of claims 13 to 22 wherein the liquid formulat'on also contains an antioxidant.

22. 24. A method according to any of claims 1 to 14 wherein a liquid formulation is applied which comprises the pyrethroid dissolved in a solvent system comprising 30-70 wt % xylene, 20-40 wt % cyclohexanone and 5-25 wt % vegetable oil.

23. 25. A method according to any one of claims I to 14 wherein a liquid formulation is applied which comprises the pyrethroid dissolved in a solvent system comprising a major proportion of diethylene glycol mono-n-butyl ether.

24. 26. A method according to claim 25 wherein the solvent system further contains a minor proportion of isopropyl myristate.

25. 27. A method according to any one of claims 1 to 11 wherein the pyrethroid is applied in the form of an aerosol.

26. 28. A method to claim 27 wherein the aerosol formulation comprises the pyrethroid dissolved in a liquid carbon dioxide propellant.

27. 29. A method according to any preceding claim wherein the pyrethroid is applied together with a dyestuff.

28. 30. A method according to any preceding claim wherein the sheep is infested with keds. 53108

29. 31. A method to any one of claim» 1 to 26 wherein the aheep I» Infested with mites.

30. 32. A method according to any one of claims 1 to 26 wherein the sheep it infested with blowfly.

31. 33. A method of controlling sheep ectoparasltesselected fromkeds, mitesandblowflies 5 which comprises the application of a formulation substantially as disclosed in any Example.

32. 34. A method substantially as hereinbefore described with reference to the Examples. Dated this 20th day of November 1981