GB2150026A

GB2150026A - Pest control

Info

Publication number: GB2150026A
Application number: GB08332685A
Authority: GB
Inventors: Peter John Kieran; Robert Bruce Townsend
Original assignee: Wellcome Foundation Ltd
Current assignee: Wellcome Foundation Ltd
Priority date: 1980-11-21
Filing date: 1983-12-07
Publication date: 1985-06-26
Also published as: GB2150026B; GB2150025A; GB2088212A; FR2494561B1; ZA818079B; GB8332684D0; IE812719L; GB2150025B; GB2088212B; ZA833066B; GB8332685D0; FR2494561A1; NZ199009A; IE52108B1

Abstract

Formulations containing a pyrethroid in a solvent system containing a glycol are provided for the control of sheep ectoparasites including lice, keds, flies, mites and ticks by the localised application to the skin or fleece of the sheep of the fomulation.

Description

1 GB 2 150 026A 1

SPECIFICATION

Pest control The present invention relates to pour-on formulations for controlling sheep ectoparasites including keds, lice, flies, mites and ticks. The invention has special application of the control of the sheep-biting louse (Damalinia ovis) and 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 10 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 has 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 Application Nos. 8134831 and 8332684 disclose and claim methods of controlling lice on sheep and of controlling keds, blow flies and mites on sheep respectively. The present invention is based on the unexpected discovery that localised applications of pyrethroids are suprisingly effective in controlling and eradicating lice. It is particularly surprising that such localised application is effective even on long-woolled merino sheep.

Thus, the present invention provides a formulation for the application onto a localised region of the skin or fleece of a sheet which comprises a pyrethroid of the formula.

215 0 X5icr t(j wherein M is -CO -c A CH =C Al 7/" 1 X2 / c \ CH3 CH3 Xl or -CO-CH-CH-CH - 11 / 1 1 X2 c \ X3 xt CH3 CH3 or - CO - CH - R2 1 1.11 CH \\ CH3 CH3 and wherein X, to X4 are independently selected from halo, C,-C, alkyl, halogen-substituted C,-C, alkyl, and halogen-substituted phenyl; X, is -H or halo; R, is -H or cyano; and R, is halogen-substituted phenyl, in a solvent system containing diethylene glycol mono-n-butyl ether.

C) ---11;.4 1; +; 11; + +k + +k +k; 14 F 1+; y oca se app ca on s mean a e pyre ro ormu a on only has to be 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 50 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 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', 55 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.

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

The pyrethroid is preferably selected from the group of fight stable pyrethroids. Deltamethrin (also known as decamethrin) is preferred and is a solid under normal conditions. Suitable pyrethroids are disclosed in Tables 1 to Ill.

2 GB 2 150 026A 2 TABLE 1

M = CO - CH - - CH - CH = C CH 3 CH 3 No. X X 2 X 3 X 4 X 5 R trivial name 1 cl cl - - H H permethrin 2 CH 3 CH 3 - H H phenonthrin 3 Br Br - H CN deltarnethrin 4 cl cl - H CN cypermethrin 2N c.,-hair..1-rin 3 6 cl 0' C- cl F' C'- N flu-nethrin 7 cl cl F CN cyfluthrin a CH 3 CH 3 - - H CN cyphenothrin 1 i 1 w 1 3 i 35.

1 GB 2 150 026A 3 TABLE II m co CH CH - CH - c 1 1 '--, X 2 c X 3 A 4 CH CH No. X1 X 2 X3 X4 X 5 RI trivial name 9 Br Br Br Br H e-N tralomethrin cl cl Br Br TABLE 111

1% ', = - No.

11 R? -CO cl H CN tralocythrin CC - CH - R 2 1 -11 ::H X 5 R 1 trivial name H CN fenvalerate 4 GB 2 150 026A 4 it is a particular advantage of the present method that only small volumes of pyrethroid or pyrethroid-containing formulations need to be applied. Depending on the size of the sheep, the volume applied will generally lie in the range 2 to 15 mi per sheep.

Depending on the efficacy of the particular pyrethroid employed, the formulation generally 5 contains from 0.1 to 500, preferably 1 to 250 mg/mi 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 sheared sheep. However, higher doses are required for full-woolled sheep.

The pyrethroid is preferably applied in the form of a pour-on formulation.

Diethylene glycol mono-n-butyl ether 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.

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 acids are useful formulation adjuncts e.g. n-butyl oleate, N,N- 15 dirnethyl oleamide and isopropyl myristate (]PM).

It has been found that the includion of an antioxidant such as 2,6-ditertbutyl-4-cresol (BHT) or 2-tert-butyi-4-methoxyphenol (BHA) has a useful stabilising effect on the active ingredients.

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

(1) COMPARATIVE TESTS The effectiveness of a number of known insecticides in controlling sheep lice using pour-on formulations was assessed. A summary of the active agents and dose rates is given in Table IV.25

TABLE IV

Chemical Pour-on (mg/kg) 30 chlorfenviriphos 100 maldison 250 carbaryl 100 dimethoate 100 35 dioxathion 100 ethion 100 fenitrothion 100 trichlorphon 100 famphur 50,100 40 ronnel 100 crotoxyphos 100 bendiocarb 100 bromophos ethyl 100 dichlofenthion 100 45 crufomate 100 naled 100 All the pour-on treatments were -formulated in a solvent system containing xylene, cylcohexa- 50 none and corn oil.

A total of 18 groups of lice-infested merino sheep divided into control (1) and treatment groups (17) were selected and treated according to Table IV.

No pour-on treatment had any significant effect on existing lice burdens.

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

6 0 Test 1 The results of the evaluation of deltamethrin on recently sheared merino sheep using a DGBEbased solvent systems are given in Table V. The results of the untreated control group are given in Table Vi.

The DGBE-based solvent system had a composition as follows:

GB 2 150 026A 5 diethylene glycol mono-n-butyl ether (DGBE) 85 wt% isopropyl myristate (IPM) 15 wt % 2,6-ditert-butyi-4-cresol (BHT) 2.59/1.

TABLE V DGBE-Based Solvent Post-Treatrent c Inspections ceP Body- D! 1 1 Chall;n9 and Group 2) nr 5n wel"t Dad Inspections tGr 1 Group tgll) 1 3 6 10 12 14 8.0 GF.DUP 2 1d) 78 4.0 81 mi4 Kg 129 GRDUP 1 ( c) so 45 5.61. 0 0 0 1 1 1 r-.g/kg 73 49 6.1 0 0 0 3 0 1 1 kg as 43 5.4 0 0 0 1 ---------------------------------------------------------------------------- 0 4 0 1 0 0 0 0 . 41 IC.3 <1 120 44 11.0 0 47 11.B 0 WC-Ur. Z (c) 62 45 5.6 0 0 0 3 2 16.0 2 74 49 6.1 0 0 0 1 B k 96 43 5.4 0 0 slauntitered (in ury) SMUT 2 (d) le 41 1C.3 0 0 0 1 0 9.0: =:; AK 9 ú9 44 11.0 0 0 0 1 1 1 m1,14 xQ 132 47 11.8 0 0 0 1 2 G RM7P 3 ( c) 86 49 6.1 1120 0 20.0 2.5 nc)lkg 107 45 5.6 0 0 1 ml/a kg 114 43 5.4 0 0 GROUP 3 (d) 91 41 10.3 0 0 10.0 2.5 ngl'Kg 94 44 111.0 0 0 1 =l /4 X9 344 47 111.8 0. 0 --------------------------------------------------------------------------------- GROUP 4 (c) 108 45 5.6 0 0 24.0 3 r=/kg 117 43 5.4 0 0 1 m! 'S Kg 120 49 6.1 0 0 -------------------------------------------------------------------------------- GROUT 4 (d) 56 40 10.0 0 0 57 46 1-1.5 0 0 44 111.0 0 0 1 14 K9 97 I5Ft-UP 5 c) 119 43 5,4 0 0 32.0 9 128 49 C.1 0 0 45 5.6 c 0 .......................................................................... .

CR_=7 5 (d) 66 40 1^..0 0 0 1ú.0 r=.-KC) 70 46 0 0 0 0 n.,'4 Kg 98 44 11.0 - -- - -- -- -- --- - - ---- --- --- --- -------- ----- ---- ------ --- --------- --- ------ -------- - WC,j"? E tc) i33 43 5.4 c 0 1:4 5 r'.m.,K9 136 i. 1 c 0 49 1 r.1 A KC 145 45 5.6 0 0 (d) 72 40 IC.0 0 0 12.0 5 9,KCJ @.7 46 ill.5 0 0 l rr.114 K9 101 44 14.0 0 0 Ficures shown in 'week' col=ns are the number c! lice seen in twenty wool partings.

6 TABLE VI

Results of Examinations of Shorn Untreated Control Group U n t r e a t e d C o n t r o 1 s Sheep Body Week Week GB 2 150 026A 6 No. weight 3 6 15 (kg) 20 51 10 10 77 56 9 8 79 52 17 15 25 82 38 24 31 54 18 29 104 28 37 35 30 52 20 a ill 29 24 23 116 44 10 16 35 122 39 22 18 123 36 19 18 130 35 is 17 40 Figures show the number of lice seen in twenty wool partings.

Test 2 (varying solvent systems) Table V11 gives the results for formulations of deltamethrin in a variety of other solvent systems when applied to recently sheared merino sheep.

7 GB 2 150 026A 7 TABLE ill various Solvent Sys Sheep Body Dose Pre- Week week Week Formulations 5 No. wt Treat- 4 6 (kg) ment 131 25 6 51 0 0 0 10 g/1 deltamethrin, 2.5 9/1 BET 132 29 6 34 0 0 0 50 ppn SUDAN RED IV 10 138 28 6 87 0 0 0 DGBEicyclohexanone (65:35 w/w) to litre 164 36 5 117 0 0 0 ----------------------------------------------------------------------------------------------------- 911 deltamethrin, 100 9/1 mineral oil 33 a 47 0 0 0 2.5 9/1 BET, 50 ppm SUDAN RED IV 177 30 4 27 0 0 0 diethylene glycol mono-n-butyl ether (DGBEi to 1 litre 15 31 8 90 1 0 0 10 g/1 deltamethrin, 2.5 g/1 BET 143 21 6 44 1 0 0 50 ppm SUDAN RED IV, dipropylene glycol 162 25 6 75 1 0 0 inonomethyl ether WPM) to 1 litre 20 129 29 - 14 14 8 17 23 - 1B 28 14 22 154 25 - - 171 47 72 Controls 36 - 17 8 8 24 171 30 - 17 29 24 20 ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Test 3 (effect of deltamethrin against keds) The efficacy of deltamethrin against infestations of merino sheep with keds (Melophagus ovinus) was determined by applying 8 mi of dehamethrin in DGBE-based solvent system given 30 in Test 1 as a backline treatment to twenty newly shorn sheep. The concentration of deltamethrin was 10 g/L All twenty sheep were re-examined 10 weeks after treatment and no live keds were found.

Test 4 (time to take effect) The time for the pyrethroid to fully clear the merino sheep following backline application fo, the liquid formulation was investigated and the results are shown in Table 4. These demonstrate that the pyrethroid takes a finite period to completely clear the sheep of lice. However, the sheep are substantially cleared within 15 days. The effect is also demonstrated in certain of the preceding Tables.

8 GB 2 150 026A 8 Table V1 I I Process of Reduction in Lice Numbers following Pyrethroid Backline Treatment.

Lice Score 5 Sheep Group No. Day 0 7 9 15 35 42 Cypermethrin 756 >20 7 3 0 21 0 10 mg/kg 746 >20 7 2 5 21 0 733 >20 9 3 0 0 0 Fenvalerate 766 >20 2 2 3 0 0 mg/kg 770 >20 6 1 0 0 0 730 >20 2 2 2 11 0 15 Flumethrin 722 >20 10 - 8 41 0 12-16 mg/kg 755 >20 19 - 10 181 31,2A 748 >20 12 - 4 71,2A 41,3A Controls 741 >20 - - 14 - 64(18) 737 >20 - - 15 - 52(18) 20 764 >20 - 16 83(19) 754 >20 - - 10 - 53(15) 758 >20 - - 22 - 121(19) 723 >20 - - 26 35(13) 25 1 = immature lice A = adult lice (11) FORMULATIONS FOR USE ACCORDING TO THE PRESENT INVENTION Suitable formulations are presented in the following Examples.

Example 1

10. 1 9 of technical deltamethrin (989 g active per kg) was dissolved in a solvent consisting of:

diethylene glycol monobutyl ether BHT antioxidant Sudan Red IV 2500 ppm 50 ppm and the volume adjusted to one litre with the same solvent to give a solution containing 10 g/] 45 deltamethrin.

Example 2

10. 1 9 of technical deltamethrin (989 g active per kg) was dissolved in a solvent blend 50 containing:

cyclohexanone 50% by weight diethylene glycol monobutyl ether 50% by weight BHT antioxidant 2500 ppm Solvent Blue No. 36 50 ppm 55 and the volume adjusted with the same solvent blend to give a solution containing 1 Og/1 deltamethrin.

Claims

1. A formulation for application onto a localised region of a sheep which comprises a pyrethroid of the formula:

9 GB 2 150 026A 9 c'k 0 -, F X5:C R1 wherein M is CH =c A X2 CH3 CH3 Xl or -CO-CH-CH-CH- 1 11 X2 c X3 X4 CH3 CH3 0' -CO-CH-R2 ..I CH \ CH3 CH3 and wherein X, to X, are independently selected from halo, C'I-C4 alkyl, halogen-substituted C, C4 alkyl, and halogen-substituted phenyl; X, is -H or halo; R, is -H or cyano; and R2 is halogen-substituted phenyl, in a solvent system containing a diethylene glycol mono-n- 25 butyl ether.

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

3. A formulation according to claim 1 or 2 wherein the pyrethroid is selected from permethrin, phenothrin, cyfluthrin, cyphenhothrin, tralomethrin, tralocythrin and fenvalerate (all 30 as herein defined).

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

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

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

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

8. A formulation according to any one of the claims 1 to 7 which comprises cypermethrin 40 dissolved in a major proportion of diethylene glycol mon-n-butyl ether.

9. A formulation according to any one of claims 1 to 10 which contains isopropyl myristate.

10. A formulation according to any one of claims 1 to 11 which further contains an antioxidant.

11. A formulation according to any one of claims 1 to 15 which further contains a dye. 45

12. A formulation according to any one of claims 1 to 13 which contains 1 to 250 mg/mi of the pyrethroid.

Printed in the United Kingdom for Her Majesty's Stationery Office. Dd 8818935, 1985. 4235 Published at The Patent Office, 25 Southampton Buildings. London, WC2A 'I AY. from which copies may be obtained.