This invention relates to novel arthropodicidal compositions, formulations containing such compositions, and to the use of such compositions or formulations in controlling pests of the Phylum Arthropoda.

The compound bis(2,3,3,3-tetrachloro-n-propyl) ether (hereinafter called the "Compound") is known from U.K. Patent No. 795 918 to synergise the insecticidal activity of the pyrethrins and of allethrin; and from Scientific Pest Control, Volume 31, pages 86-90 the Compound is also known to synergise the insecticidal activity of tetra- methrin. Although the Compound itself possesses some pesticidal activity, it is mainly known as a pyrethroid syncrgist to render the use of expensive pyrethroid pesticides more economic.

For this purpose amounts of the Compound in the range of from 1:1 w/w to 1:10 w/w, ratio pyrethroid (or of 'pyrcthrins') to synergist, have been recommended.

The compound bis(2,3,3,3-tetrachloro-n-propyl)ether may be prepared as described in Japanese Patent Application, Publication No. 77/016089.

It has now been found that the Compound is capable of lowering the effect on humans of certain irritant properties of the synthetic pyrethroids:

• 5-benzyl-3-furylmethyl(±)-cis (lR, 3S, E)-2,2-dimethyl-3-(2-oxo-2,3,4,5-tetrahydro-3-thienyli- denemethyl)cyclopropanecarboxylate (kadethrin), described in U.K. Patent No. 1 308 650, and
• (-)-α-cyano-3-phenoxybenzyl-2,2-dimethyl(+)-cis-3R-(2,2-dibromovinyl)cyclopropane-lR-carboxylate (decamethrin), described in U.K. Patent No.

1 448 228 [hereinafter referred to as the "Esters"]. Concentrations of the Compound which may be used to lower the irritant effect on humans of pyrethroids lie in the range of from 1:0.5 w/w to 1:50 w/w, ratio pyrethroid to the Compound.

The irritant effect of the Esters on humans may result in scveral symptoms which include ocular irritancy such as watering of the eyes; nasal irritancy such as running of the nose, sneezing and the perception of an unpleasant smell; irritation of the pharynx such as coughing and a dry throat; buccal irritancy such as a dry mouth and numbed lips; dermal irritancy; and lingual irritancy such as a sensation of a tingling of the tongue. When the Esters are used in combination with the Compound, there is a reduction in both the degree andthe frequency of occurrence of such symptoms.

A composition of the present invention containing the Ester decamethrin is of particular value as a killing agent, and its knock-down activity may be enhanced by the inclusion in the composition of a further pyrethroid having potent knock-down properties. Such compounds include kadethrin, (±)-allethrolonyl-(+)-trans- chrysanthemate (bioallethrin) and (-)-allethro-_. lonyl-(+)-trans-chrysanthemate (S-bioallethrin).

On the other hand, as indicated above, kadethrin is itself a particularly good knock-down agent, and its lethal properties may be enhanced by including in compositions of this invention a more lethal agent preferably having good residual properties. Such compounds include decamethrin, 5-benzyl-3-furylmethyl-(+)-trans-chrysanthemate (bioresmethrin), 3-phenoxybenzyl-(±)-cis, trans-2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropane-1-carboxylate (permethrin) and 3-phenoxybenzyl-(+)-cis, trans- chrysanthemate (D-phenothrin).

The effectiveness of the compositions of this invention may be enhanced by combination with a pyrethroid synergist well known in the art. Such synergists include piperonyl butoxide, piprotal, sulfoxide, n-propyl isome and octyl- bicycloheptenedicarboximide (MGK 264®).

The compositions of this invention may be used to control pests of the Phylum Arthropoda, especially flying and crawling members of the Class Insecta, in particular mosquitoes, cockroaches and house-flies.

The compositions of this invention may be used for such purposes as a simple mixture of the active ingredients or, preferably, may be presented as an arthropodicidal formulation in combination with one or more of the following:- wetting, dispersing, surface-active, stabilising, thickening or emulsifying agents, or other standard solvents, propellants, diluents, inerts or carriers used and known in the art when formulating pesticides.

Dusting powders may be prepared by intimate admixture of the active ingredients with a powdered solid inert carrier. Suitable carriers include clays, silicas, kaolin, talcs, powdered chalk, calcium carbonate, Fuller's Earth, gypsum, diatomaceous earths and vegetable carriers.

Spray formulations of this invention may comprise a solution in an organic solvent or a suspension in water prepared either from a water miscible oil or a water dispersible powder. The miscible oil or wettable powder comprises a mixture of the active ingredients with or without an organic solvent and one or more emulsifiers. The spray may be presented either as a pure solution, a water-based emulsion, an oil-based emulsion or a suspension. The spray formulations of this invention may be applied to the arthropod pests by means well known in the art such that the droplet size and dispersion of the spray depends on the mechanical device employed. Coarse sprays may be applied manually by means of knapsack-sprayers or hand sprayers. Finer sprays may be obtained by utilising spinning- disc sprayers which may be applied at ground level or from above in order to effect extensive aerial coverage of the environment involved. Such machines depending upon rotary atomisation may be driven electrically or by propellers rotated by forward motion of the aircraft employed. Ultra-low volume and thermal fogging devices may also be utilised in order to present the spray compositions as dense clouds, fogs or mists.

Pressure packed formulations of this invention may be presented either as powder aerosols but preferably as liquid aerosols. Powder aerosols contain a mixture of the active ingredients, the Compound, optionally combined with a pyrethroid synergist, with a suitable solvent, propellant and co-solvent together with an inert finely divided solid carrier.

Liquid pressure-packed aerosol formulations consist of a mixture of the active ingredients together with a solvent and a propellant and with or without a co-solvent. Suitable solvents include chlorinated hydrocarbons such as methylenechloride or 1,1,1-trichloroethane, hydrocarbons of suitable volatility such as isopentane or cyclohexane, esters and alcohols. Propellants include volatile liquids, gases liquified under pressureand gases dissolved under pressure in the solvent. The most commonly used volatile liquid propellants are fluorinated chlorinated hydrocarbons such as fluorodichloromethane, fluorotrichloromethane, difluorodichloromethane, and 1,1,2,2-tetla- fluoro-1,2-dichloroethane. Gases which may be liquified under pressure and used as propellants include hydrocarbon gases such as propane or butane and mixtures thereof. Gases which may be used under pressure as propellants include amongst others carbon dioxide and nitrous oxide. Water/hydrocarbon or water/fluorochlorocarbon emulsions such as butane/water or di-fluorodichloro- methane/water emulsions may also be used as propellants.

A liquid aerosol formulation may contain an additional co-solvent which is less volatile than the solvent and includes suitable distilled petroleum fractions such as kerosene. The arthropodicidal liquid pressure packed formulations of this invention may comprise from (0.001-5%) of a killing pyrethroid, from (0.001-5%) of a knock-down pyrethroid, optionally from (0.010-20%) of a pyrethroid synergist, from (0.005-10%) of the Compound, from (0-99.5%) of a suitable propellant, from (0-99.5%) of a suitable solvent and from (0-40%) of a suitable co-solvent.

The preferred compositions of this invention comprise (0.005-3%) of a killing pyrethroid, from (0.005-1%) of a knock-down pyrethroid, optionally from (0.005-3%) of a pyrethroid synergist and from (0.2-2%) of the Compound.

The following Examples illustrate aspects of this invention but in no way are to be construed as a limitation thereof:

EXMIPLE 1

Spray formulations

Odourless kerosene to 100 vols. 100 vols.

EXAMPLE 2

Dusting Powder formulations

EXAMPLE 3

Miscible Oil Formulations

EXAMPLE 4

Wettable Powder Formulations

EXAMPLE 5

Irritant effect test

Six volunteers were exposed for 4 minutes to the atomized spray of an oil-based, pressure-packed formulation (A) comprising 0.025% kadethrin, 0.038 % bioresmethrin, 0.25% piperonyl butoxide and 0.50% of the Compound. The number of volunteers responding 1 hour after exposure was noted. The response was assessed twice by repeating the experiment and then compared with the response of the same panel of volunteers exposed twice to a control formulation (B) comprising 0.025% kadethrin, 0.038% bioresmethrin and 0.25% piperonyl butoxide.

The results are illustrated in Table 1.

EXAMPLE 6

Pressure-packed Formulations