GB2068732A - Improvements in or relating to ectoparasiticidal compounds - Google Patents

Abstract

Disclosed is a method of controlling ectoparasites of the order Acari in animal livestock which comprises applying to the animal an effective amount of a 4-alkylaminoquinazoline where the alkyl radical has 8 to 11 carbon atoms, e.g. 4(n-C9H19NH) quinazoline or 4(n-C10H21NH) quinazoline.

Description

SPECIFICATION Improvements in or relating to organic compounds The present invention relates to the combatting of certain ectoparasites of considerable economic significance.

In the rearing of animal livestock such as cattle and sheep, estoparasites such as the tick cause enormous losses particularly as disease vectors.

Accordingly, the present invention provides a method of preventing and/or combatting ectoparasites of the order Acari in animal livestock which comprises topically applying to the animal an effective amount of a compound of formula I,

wherein R is C5-11alkyl.

R may be branched or unbranched, and is prefer ably Cm~10 alkyl.

R is preferably unbranched.

4 - Alkylamino - quinazolines as well as their fung icidal and acaricidal use are known i.a. from the DOS 1,642,333. Several compounds of formula I in salt form are specifically disclosed in this DOS. It has now surprisingly been found that the compounds of formula I are useful in preventing and/or combatting ectoparasites of the order Acari, especially against ticks.

These unexpected properties of the compounds of formula I are of considerable significance since there are rather few pesticides that can effectively be used against ectoparasites.

The control of ectoparasites is indeed very problematic, since numerous strains ofticks have developed resistance to a wide range of pesticides such as arsenic, hexachlorohexane, camphechlor, DDT, pyrethrines, carbamates and phosphorous compounds, having various primary sites of attack in the ectoparasite. It is therefore generally accepted, that it is highly desirable to develop active substitutes for the pesticides actually used for ectoparasite control, and particularly to develop substitutes which are chemically completely different from the compounds used hitherto for that purpose.

It has now surprisingly been found that the compounds of formula I are useful in controlling ectoparasites of the order Acari. Compounds belonging to the class of aminoquinazolines have hitherto not been suggested for use in control of ectoparasites.

Moreover, compounds structurally very closely related to compounds of formula I, e.g. the compound 4 - (n - C12H2sNH) - quinazoline, show despite significant acaricidal activity only a week effect in the tests executed for evaluation of activity against ectoparasites of the order of Acari, whereas the compounds of formula I, especially the compounds of formula I wherein R is Cs- or C10alkyl, particularly wherein R is n-Cg-H19 or n-C10H21 are particularly effective in the method of the invention.

The compounds of formula I are applied to the ectoparasites of the order Acari, in free base form or in agriculturally acceptable acid addition salt form e.g. as hydrochloride or acetate, by topical treatment of the animals, e.g. by dusting, by dipping or by spray treatments with dilute aqueous form. The compounds of formula I are preferably used in free base form. The degree of dilution may vary although preferably a concentration in the range of 0.01 to 5.0%, particularly of 0.02 to 0.1%, by weight of the active agent is employed. The treatment is preferably repeated at intervals of between 7 to 21 days.

The active agent is conveniently formulated as a dust, dust concentrate, wettable powder, emulsifiable concentrate or as a solution, with conventional solid or liquid adjuvants. Particularly preferred compositions of the invention are liquid concentrates, especially those containing preferably 3.0 to 50% by weight of active agent, to be diluted with water before use. Such liquid concentrate preferably includes an emulsifying agent such as a polyglycolether derived from a high molecularweight alcohol, mercaptan or alkyl phenol with a alkylene oxide as well as a diluent such as a liquid aromatic hydrocarbon or mineral oil.

The ectoparasites of the order Acari against which the compounds of formula I have been found to be particularly effective are of the family Ixodidae e.g.

the cattle ticks such as Boophilus spp e.g. Boophilus microplus. Boophilus decolatus and Boophilus annulatus; Rhipicephalus spp such as Rhipicephalus sanguineus, Rhipicephalus appendiculatus; Rhipicephalus pulchellus and Rhipicephalus evertsi; Hyalomma spp such as Hyalomma truncatum, Hyalomma rufipes, Hyalomma detritum, Hyalomma marginatum, Hyalomma dromedarii and Hyalomma anatolicum excavatum; Amblyomma spp such as Amblyomma variegatum, Amblyomma herbraeum, Amblyomma pomposum, Amblyomma americanum, Amblyomma cayennenese, Amblyomma maculatum, Amblyomma gemma and Amblyomma lepidium; ofthefamilyArgasidae, e.g.

Otobius spp such as Otobius megnini and Ornithodoros spp such as Ornithodoros savignyi, Ornithodorus lahorensis and Ornithodoros tholozani; of the family Psoroptidae e.g. Psoroptes ovis and Psoroptes equi; and of the family Sarcoptidae e.g. Sarcoptes bovis or Sarcoptes scabici.

The invention is illustrated by the following.

Test Female fertilized adults (completely sucked with blood) of Boophilus microplus Biarra (organophosphorester- resistant strain) and Boophilus microplus Mt Alford (organophosphorester - resistant strain) are dinto test solutions of 0.2 and 0.05% of 4 - (n C10H21 NH) quinazoline by weight in water during 5 minutes. The ticks were dried in a sieve and then, for 30 seconds, upon a filterpaper.

The ticks were kept separate in glass tubes closed with gauze at 27O and 90% relative humitity. The observations made are set out in the following table.

Concentration % 0.2 0.05 Ticks Bifl) At(21 Bi Al dead ticks before begin 92 70 55 55 of oviposition (six days after treatment;; % mortality) time until oviposition 2.0 2.4 2.6 2.3 begins (in days) time until larvae - - 28 28 emerged (in days) suppression of capacity of reproduction compared with control) 100 100 92 89

(1) Bi = Boophilus microplus Biarra (2) Al = Boophilus microplus MtAlford Analogous results are obtained with 4 - (n-C9H19NH) quinazoline 4-(n-C"H23NH) quinazoline The best results are obtained with compounds of formula I in base form.

EXAMPLE A herd of cattle severely infested with the cattle tick Boophilus microplus are sprayed at 21 day periods with a 0.05 % by weight aqueous solution of 4- (n-C9H19NH) - quinazoline. The spraying is effected on the cattle individually by means of a spray race.

The cattle enter and leave the spray race through stoutly built races, the spray being applied at a pressure of 1.4kg/cm2 delivering 810 litres of wash per minute. The spray race is so designed that the whole skin surface of each animal is completely and thoroughly treated. The treatment is found to significantly reduce the tick infestation over the period of the treatment.

Analogous results are obtained with 0.05 % by weight aqueous solutions of 4 - (n-C,OH2, NH) quinazoline.

Claims (12)

1. A method of preventing or combatting ectoparasites of the order Acari in animal livestock which comprises topically applying to the animal an effective amount of a compound of formula I,

wherein R is Ca-ii alkyl.

2. A method according to Claim 1, wherein R is C9- or C10alkyl.

3. A method according to Claim 1 or 2, wherein R is straight chain alkyl.

4. A method according to any one of Claims 1 to 3, wherein the ectoparasites are of the families Ixodidae, Argasidae, Psoroptidae or Sarcoptidae in animal livestock.

5. A method according to Claim 4, wherein the ectoparasites are Boophilus spp, Rhipicephalus spp, Hyalomma spp, Amblyomma spp, Otobius spp or Ornithodoros spp.

6. A method according to any preceding claims, wherein the compound of formula I is applied from a dilute aqueous solution by spraying or dipping the animal.

7. A method according to Claim 6, wherein the active agent is applied as a 0.01 to 5.0% by weight aqueous solution.

8. A method according to Claim 6 wherein the active agent is applied as a 0.02 to 0.1% by weight aqueous solution.

9. A method according to any preceding claims wherein the compound of formula I is in base form.

10. A method according to any one of the preceding claims for the treatment of cattle or sheep.

11. A method according to Claim 1, substantially as hereinbefore described, with reference to the Example.

12. A vendible pack containing a compound of formula las defined in Claim 1, and having, in physical relationship therewith, printed directions specifying the use for control of ectoparasites in accordance with the method of any of Claims 1 to 11.