GB2137497A - Bait for attracting ectoparasites - Google Patents

Abstract

o-Nitrophenol is used as a bait for ectoparasites, particularly for those of the subclass Acarina, and can be used, alone or in admixtures with further phenols, alcohols, ethers and/or carboxylic acids. The o-Nitrophenol can be formulated with an ectoparasiticide e.g. a pyrethrin or pyrethroid.

Description

SPECIFICATION Bait and mixtures thereof for attracting ectoparasites The present invention relates to the use of ortho-nitrophenol alone or in admixture with suitable additives as bait (= pheromone) for ectoparasites, and to novei bait mixtures in which ortho-nitrophenol is the essential constituent.

Within the subclass Acarina, there are ectoparasites which, as pests and disease carriers, create serious problems in veterinary and human medicine. They are primarily blood-suckers, which feed on blood, lymph, cells or liquified tissue, and which belong mainly to the orders: Gamasida, Ixodida, Actinedida, and Acaridida. Among the Sarcoptiformes, Sacoptidae and Psoroptidae are notorious as pathogens of scabies and mange in the case of mammals.

The transitions from ecto- to endoparasites are moreover fluid. Mites can thus also become endoparasites in three ways: 1. ectoparasites penetrate from the outside into the cutaneous tissue, as is shown for example by the behaviour of itch mites (Sarcoptidae); 2. ectoparasites penetrate into inner air cavities, for example into the nasal cavity, into the lung, into the laryngocele and into the trachea; and 3. ectoparasites penetrate into the intestines.

The invention accordingly relates also to such ectoparasites which produce endoparasitic symptoms.

A large proportion of blood-suckers belong to the polyvalent species, of which the various development stages, namely larvae, nymphs and adults, parasitise on or in different hosts, a factor which greatly increases the number of quite differing syndromes. Thus, for example, larvae and nymphs of the genus Amblyomma, which belongs to the Ixodidae family, infest small mammals and birds, whilst on the other hand nymphs and adults of the same genus parasitise on a great number of larger mammals (including humans). The tropical bont tick Amblyomma variegatum alone is a primary and widely distributed carrier of Cowdria ruminantium, the pathogen of heart-water disease in cattle, sheep and goats; it is also a carrier of 0 fever (Coxiella burnetl) and of tick typhus (Rickettsia conori).The deep and coarse bite of this tick also causes inflammatory wounds difficult to heal, the presence of which facilitates infestation by further parasites (Dermatomyasis and Dermatophilosis).

The discovery of more and more novel methods of control and of the means for carrying them out is an urgent requirement.

In addition to the purely acaricidal or parasiticidal chemical control, numerous attempts have been made to specifically interrupt in another manner the life cycle of the parasites. One of these attempts consists in the interruption of the sensorial transmission systems of adult insects, which can cause confusion of the pests or can lead to them being repelled. Sex pheromones in particular can be used to confuse the adult pests, to induce them for example to gather at a point, where they can be subsequently combated.

Since 2,6-dichlorophenol was able to be identified as a sex pheromone of the lone-startickAmblyomma americanum L. (R.S. Berger, Science 177,704-705 [1972]), this phenol derivative has been verified as being a sex pheromone also in the case of further metastriate tick genera, such as Rhipicephalus, Dermacentor and Hyalomma. A general role for this compound and especially for p-cresol and salicylaldehyde as pheromones for metastriate ticks has been discussed (D. Kellum and R.S. Berger, J. Med. Entomol.9,67-70 [19771).

It has on the other hand now been found, and this finding forms the subject matter of the present invention, that the use of o-nitrophenol as a communication substance among pests of the order Acarina, particularly for metastriate ticks, offers far greater possibilities of producing a confusing effect than do the aforementioned substances. o-Nitrophenol can be used on its own, or in admixture with further sensorial components, as an aggregation pheromone, that is to say, as a substance which puts adult insects into a state of excitement, and induces them to move about as close as possible to this compound.

The areas sensorially accentuated in this manner, for example on the host animal or in its vicinity, can be treated with suitable parasiticides, which effect a rapid killing of the pests. In the case of Amblyomma species, for example A. variegatum, A. hebraeum, A. maculatum, and so forth, o-nitrophenol acts as a pheromone both on male insects and on female insects.

In contrast to the behaviour of most metastriate tick species, where it is mainly the partially fed females that attract, with a sex pheromone, engorged males ready for copulation, the behaviour of many Amblyomma species is such that it is the sexually active males engorged with blood which attract the unfed females, and also males, with an aggregation pheromone, and incite them to stay in the immediate proximity. In the case of these species, the still unfed females settle only in the presence of engorged mature males, or of an extract thereof, on the host animal. The males for their part require for the complete development of their gonads a blood feed lasting several days. The release of pheromone does not commence until sexual maturity is attained.

By virtue of this visibly complicated behaviour pattern, such as that described here just for three tick species by way of example, and which in the case of other species thereof again deviates in a characteristic manner, it is very easy to induce, with traces of 0.01-1 Fg of o-nitrophenol or of 0.001-0.1 mg of o-nitrophenol per ml of solvent, or per ml of a corresponding mixture with potentiating, volatile and/or applicationpromoting additives, confusion effects on the pests to such an extent that copulation and blood intake are prevented. If the adult pests are not killed in situ on the host animal with suitable pesticides, a further opportunity is provided for doing this on the ground onto which they drop when copulation does not occur.

The producing of confusion by means of o-nitrophenol or o-nitrophenol mixtures and the killing process are therefore two separate operations, which can however be combined. Both the combined operation and the sequence of operations constitute process steps according to the present invention.

It is to be pointed out that acaricides exist which contain in the molecule structural elements of a nitrophenol, for example, 4,6-dinitro-2-cyclohexylphenol or 4-nitro-2,6-ditert-butylphenol, which are effective in particular against Tetranychidae. There are however neither indications of the fact that such acaricides from the "nitrophenol" series would have a pheromone effect, nor indications on the other hand that o-nitrophenol would have any acaricidal or ectoparasiticidal activity.

It is therefore very surprising that the individual compound o-nitrophenol can be used for the influencing of the behaviour of pests of the order Acarina.

Further subject matter of the invention concerns the specific intensification of the attraction effect of o-nitrophenol by means of suitable additives, among which being those of the same phenol class of substances Phenols particularly suitable are those which carry a second substituent in the ortho position with respect to the OH group, preferably an electron-attracting substituent or halogen.

Examples of such phenolic additives which may be mentioned are: o-halophenol, 2,6-dihalophenol, salicylaldehyde, o-nitrosalicylaldehyde, salicylic acid, salicylic acid-(C1-Ca2)-aliphatic esters, o-nitrosalicylic acid or C1-C12-aliphatic esters thereof, eugenol, guajacol, pyrocatechin, o-hydroxyacetophenone, o- hydroxypropiophenone or a higher homologue, o-hydroxybenzonitrile, saligenin, 2-haloresorcinol, 2nitroresorcinol, vanillin, o-hydroxybenzenesulfonic acid or C1-C12-aliphatic esters thereof. Salicylic acid-(C1 C4)-alkyl esters, -allyl esters or -propargyl esters are very advantageous components for combinations. Also suitable is 2,6-dichlorophenol.

Other additives for increasing the attraction effect are alcohols up to a mean chain length of 2-10 C atoms, which can be polyhydric and fully or partially etherified by alkyl. Examples of such C2-C10 compounds are: ethanol, n-butanol, glycol, glycerol, ethyiene glycol monomethyl ether, diethylene glycol mono-n-butyl ether, isoamyl ethyl ether, and so forth. Further additives for intensifying the attraction effect of o-nitrophenol are aliphatic C6-C18-carboxylic acids, among which may be mentioned: caprylic acid, enanthic acid, capric acid and oleic acid. Pelargonic acid can be very advantageously used.

The aforementioned additives need not necessarily be independent attractants, although they may contribute in this respect; by virtue mainly however of their dispersing properties, dissolving behaviour, lipophil character, partial water-solubility, polarity or other physiochemical characteristics, they intensify the pheromone effect of the o-nitrophenol. In general, 0 to 3, preferably 1 to 3, such additives (denoted here and in the following as "important constituents" suffice to increase the bait effect of the o-nitrophenol. It has been shown that mixtures have a greater attraction effect than pure o-nitrophenol.

In addition, the bait mixtures according to the present invention can contain further formulation auxiliaries which render possible their use in practice in the form of solutions, emulsions, suspensions, lotions and ointments. Such preparations correspond largely to those customarily used in formulation practice, with which one skilled in the art is familiar. It must however be ensured that the odorous component of the o-nitrophenol and that of other phenols, alcohols or carboxylic acids is not masked or concealed, or neutralised by basic additives (and hence by conversion into salt form). Water is a borderline case between "important constituent" and formulation auxiliary.

The present invention relates also to bait mixtures having o-nitrophenol as the essential constituent, which at the same time contain an ectoparasiticide. Particularly suitable for this purpose within the scope of the present invention are natural pyrethrins and synthetic pyrethroids. Suitable pyrethroids for the simultaneous or subsequent controlling of ectoparasites are in particular those of the following formula P

wherein M is any one of the radicals

and wherein XX1, X2, Xs and X4 independently of one another are each fluorine, chlorine, bromine, methyl, trifluoromethyl, and X is also p-chlorophenyl, X5 is hydrogen or fluorine, and R1 is hydrogen, cyano or ethinyl, whilst R2 is phenyl, phenoxy or phenyiamino, which is unsubstituted or substituted in the phenyl nucleus by chlorine, methyl ortrifluoromethyl, and Y1 and Y2 are hydrogen, or together form a double bond.

Preferred pyrethroids are: phenothrin, permethrin, cypermethrin, decamethrin (= deltamethrin), panecto (= Cl 206'797), cyhalothrin, flumethrin, cyfluthrin, tralomethrin, tralocythrin, fenvalerate, fluvalinate (= mavrick).

Host animals which can be treated preferably at a point with o-nitrophenol or with a bait mixture according to the present invention are essentially all domestic and productive animals which are subject to infestation by ectoparasites, especially those of the order Acarina. Examples are hoofed animals (such as cattle, sheep, goats, red deer, horses and pigs), poultry (fowl, geese, ducks, turkeys, pigeons, song-birds and cage-birds) and fur-bearing animals (dogs, cats, minks and guinea pigs).

BIOLOGICAL EXAMPLE 1 Evidence of the bait (attractant) effect of o-nitrophenol In the so-called arena test, a filter paper (Macherey-Nagel No. 713/8 cm it) is laid out in each of the four corners of a plexiglass chamber (34 x 17 x 20 cm), and in each corner is placed a metal capsule with a wire mesh at both ends. There are then applied to a plug of cotton wool within the capsule in the test-sector corner 10 Fl of a 0.03% diethyl ether solution of o-nitrophenol, and in the remaining sectors, in each capsule, 10 il of pure diethyl ether. The ether is evaporated off in each case before commencement of the test. For each test, 40 ticks are placed in the center of the chamber.The dispersion of the ticks over the four sectors is determined, in the sense of a primary preference, 10 minutes after the start of the test, and the results are analysed. The test is performed in an incubator under constant conditions, and each test is repeated six times.

At the concentration of 0.003 mg of o-nitrophenol, 20-25 ticks remained actively searching mainly in the test eorner. The remaining ticks were wandering around in the free space of the arena.

A raising of the o-nitrophenol concentration in the test solution to 0.3 and 3% (applied amounts 0.01 and 0.1 mg, respectively) produced no further increase of the primary attraction.

BIOLOGICAL EXAMPLE 2 In the arena test as described in Example 1, o-nitrophenol mixtures of the following compositions were tested: A. 30 mg of o-nitrophenol, 15 Fl of pelargonic acid, and 10 Al of methyl salicylatein 100 ml of diethyl ether.

Application in the test corner: 10 cLI pl 0.01 ml).

B. 50 mg of o-nitrophenol, 30 Fl of capric acid, and 15 Al of guajacol in 100 ml of diethyl ether.

Application in the test corner: 10 iil.

C. 120 mg of o-nitrophenol, 20 pl of caprylic acid, 20 l of ethyl salicylate, and 5 Fl of glycerol (or glycol) in 100 ml of acetone.

Application in the test corner: 10 pI.

With the bait mixtures A, B and C given in the foregoing, there was obtained in each case a higher attractivity of on average 24-32 ticks in the test corner. Furthermore, the ticks no longer left the preferred corner after they had once migrated to it. The remaining insects wandered about in the arena.

The comparative test solutions A', B' and C' not containing o-nitrophenol, which were tested in parallel tests, had no attraction for the ticks. A random dispersion of the ticks was observed in the arena after 10 minutes.

Further examples of mixtures D) 50 mg of o-nitrophenol, 20 mg of o-chlorophenol, and 25 lli of glycerol in 100 ml of ethanol; E) 80 mg of o-nitrophenol, 55 mg of o-hydroxyacetophenone, 10 SLI of caprylic acid, and 90 111 of diethylene glycol mono-n-butyl ether; F) 120 mg of o-nitrophenol, 30 Fl of pelargonic acid, and 5 yl of glycerol in 100 ml of methyl ethyl ketone.

Examples of bait mixtures with pyrethroid additive G) B + 1 to 250 mg of cypermethrin; H) D + 1 to 250 mg of fenvalerate; I) E + 1 to 500 mg of cypermethrin; J) F + 1 to 300 mg of decamethrin; K) 30 mg of o-nitrophenol, 15 pl of pelargonic acid, 10 ,al of glycerol, and 400 mg offlumethrin orcyfluthrin in 100 ml of diethyl ether; L) 30 mg of o-nitrophenol, 120 l of pelargonic acid, 15 ,ul of methylsalicylate, 300 mg of pyrethroid (for example cypermethrin, decamethrin, fenvalerate, flumethrin or cyflumethrin) in 100 ml of xylene or 100 ml of hexane/dichloromethane or 100 ml of ethyl acetate.

Claims (22)

1. Use of ortho-nitrophenol alone or in admixture with additives as bait for ectoparasites.

2. Use according to claim 1 for ectoparasites of the orders: Gamasida, Ixodida and Actinedida, and Acaridida of the subclass Acarina.

3. Use according to claim 2 for Acarina of the order Ixodida of the genus Amblyomma.

4. Use according to claim 1, wherein there is used, as additive, a further phenol compound which carries, in at least one ortho-position, a substituent.

5. Use according to claim 4 wherein the further phenolic compound carries in at least one ortho-position an electron-attracting substituent or halogen.

6. Use according to claim 4, wherein the additive is selected from the group comprising: o-halophenol, 2,6-dihalophenol, salicylaldehyde, o-nitrosalicylaldehyde, salicylic acid, salicylic acid-(C1-C12)-aliphatic esters, o-nitrosalicylic acid or C1-C12-aliphatic esters thereof, eugenol, guajacol, pyrocatechin, ohydroxyacetophenone, o-hydroxypropiophenone or a higher homologue, o-hydroxybenzonitrile, saligenin, 2-haloresorcinol, 2-nitroresorcinol, vanillin, o-hydroxybenzenesulfonic acid or C1-C12-aliphatic esters thereof.

7. Use according to either claim 1 or 4, wherein the additive used is an aliphatic C6-C18-carboxylic acid.

8. Use according to claim 7, wherein pelargonic acid is used.

9. Use according to claim 1 of o-nitrophenol as essential constituent in a mixture containing, as further important constituents, at least one phenol according to claim 4 and at least one aliphatic C6-C18-carboxylic acid.

10. Use according to claim 9, wherein an ectoparasiticide is used as further constituent.

11. Bait mixture for ectoparasites, which mixture contains ortho-nitrophenol as essential constituent as well as at least one of the following components: a) a phenol with the exception of o-nitrophenol, which carries, in at least one ortho-position, a substituent; b) an aliphatic C6-C18-carboxylic acid; and c) an optionally polyhydric alcohol, which is optionally fully or partially etherified by alkyl and has a mean chain-length of 2-10 C atoms; besides optionally further solvents and/or dispersing agents.

12. Bait mixture according to claim 11 in which component a) is a phenol which carries in at least one ortho-position an electron-attracting substituent or halogen.

13. Bait mixture according to claim 11, which contains, as component a): o-halophenol, 2,6dihalophenol, salicylaldehyde, o-nitrosalicylaldehyde, salicylic acid, salicylic acid-(C1-C12)-aliphatic esters, o-nitrosalicylic acid or C1-C12-aliphatic esters thereof, eugenol, guajacol, pyrocatechin, ohydroxyacetophenone, o-hydroxypropiophenone or a higher homologue, o-hydroxybenzonitrile, saligenin, 2-haloresorcinol, 2-nitroresorcinol, vanillin, o-hydroxybenzenesulfonic acid or C1-C12-aliphatic esters thereof.

14. Bait mixture according to claim 11, which contains pelargonic acid as component b).

15. Bait mixture according to claim 11, which contains glycol or glycerol as component c).

16. Bait mixture according to claim 11, which additionally contains an ectoparasiticide.

17. Bait mixture according to claim 16, wherein the ectoparasiticide is a pyrethroid.

18. Bait mixture according to claim 17, which contains an ectoparasiticide selected from the group comprising: cypermethrin, decamethrin, fenvalerate, flumethrin and cyfluthrin.

19. Process for interrupting the life cycle of ectoparasites which process comprises the application of a bait mixture according to any one of claims 13 to 18 to points on suitable parts of the body of the host animal, and the combating of the male and/or female parasites which have concentrated at those points.

20. Process according to claim 20 wherein the ectoparasite is Acarina of the subgroup Metastigmata.

21. Use according to claim 1 substantially described with reference to either of the Examples.

22. Bait mixture according to claim 11 substantially as described with reference to either of the Examples.