GB2174908A - Controlling cockroaches using (s)-(+)hydroprene - Google Patents

Abstract

Cockroach populations are controlled using the (S)-(+) enantiomer of hydroprene (Ethyl (2E, 4E)-3,7,11-trimethyl-2,4-dodecadienoate), which has superior juvenile hormone activity to the (R)-(-) enantiomer. Compositions for this purpose comprise (a) (S)-(+) hydroprene; (b) a diluent; and (c), where the diluent is a solvent, a propellant, a surfactant or a thickener.

Description

SPECIFICATION Novel compositions and methods for controlling cockroaches This invention relates to novel compositions and methods for controlling cockroach populations using the (S)-(+) enantiomer of hydroprene.

Hydroprene is ethyl (2E,4E)-3,7,11 -trimethyl-2,4-dodecadienoate. It is known to have juvenile hormone activity on insects e.g. cockroaches such as Blattella germanica (see i.a. J. Econ Entom (1975) 68:46-48).

There is an asymmetric carbon atom at C-7 in hydroprene and, accordingly, there are R and S enantiomers of the compound. JAgric Food Chem (1978)26:542-550 reports comparative juvenile hormone activity tests on (S)-(+) hydroprene, (R)-(-) hydroprene and the racemic mixture onAedes aegypti, Galleria mellonella, Tenebrio molitor, Musca domestica, and Heliothis virescens. These tests showed that the (S)-(+) enantiomer showed approximately twice the activity of the racemic mixture on these insect species.

It has now surprisingly been found that (S)-(+) hydroprene exhibits-unexpectedly superior juvenile hormone activity on cockroaches relative to racemic hydroprene.

Accordingly, one aspect of the invention is a method of cockroach population control comprising administering a cockroach reproduction inhibiting amount of (S)-(+) hydroprene to the locus infested by said population.

The term (S)-(+) hydroprene as used herein is intended to relate to hydroprene comprising substantially more than 50% by weight of the (S)-(+) enantiomer. Preferably the hydroprene used in the invention is composed predominantly of (S)-(+) hydroprene, i.e. comprises more than 75% by weight of (S)-(+) hydroprene. More preferably, the hydroprene contains less than 10%, particularly less than 5% by weight of the (R) enantiomer and is most preferably substantially free of the (R) enantiomer (i.e. contains less than 2% by weight of the (R) enantiomer).

Another aspect of the invention is a pest controlling composition comprising: a) (S)-(+) hydroprene b) a diluent and c) where the diluent is a solvent, at least one adjuvant selected from a propellant, a surfactant and a thickener (hereinafter composition of the invention).

The term diluent as used herein means any liquid or solid agriculturally acceptable material which may be added to the active ingredient to bring it in an easier or improved applicable form. It includes carriers and solents and can for example by calcium carbonate, talc, kaolin, clay, diatomaceous earth, resins (such as polyvinyl chloride, polyester urethane ethylene vinyl acetate, polypropylene), polyethylene, xylene, a petroleum solvent (including ligroin, benzin, naphta, a hydrocarbone such as pentane, hexane, octane), an alkanol such as isopropanol, a chlorinated hydrocarbon (e.g. CH2CI2, CCI3CH3), glycol monoalkylether, water and the like.

The term propellant relates to a n an agriculturally acceptable liquified gas which is self pressurised in a container having a valve and comprising a pest controlling composition, which gas forces the contents from the container when the valve is activated.

The term surfactant relates to an agriculturally acceptable material which imparts emulsifiability, spreading, wetting, dispersibility or other surface-modifying properties of the pest controlling composition of the invention.

The term thickener relates to a material which increases the viscosity of a liquid.

(S)-(+) hydroprene may be obtained in a manner known per se by resolving hydroprene into the (S) and (R) enantiomers or by synthesizing it from a resolved starting material.

(S)-(+) hydroprene exhibits a unique combination of properties vis-a-vis otherjuvenoids that makes it remarkably effective as a cockroach population control agent.

It is persistent in the environments that cockroaches inhabit. It is sufficiently volatile to translocate from one surface to another and thus penetrate into cockroach harborages, redistribute therein, and remain accessible to resident cockroach populations. Further, (S)-(+) hydroprene is effective in inducing sterility in cockroaches as well as having otherjuvenoid activities. This property is essential to effective cockroach eradication. Finally, (S)-(+) hydroprene has a high level of activity. Its superior activity relative to racemic hydroprene means that it is much more economical to use and provide less contamination of food and the human habitat than the racemic mixture.

In this regard, substantiatly pure (S)-(+) hydroprene has been found to provide German cockroach reproduction control in the laboratory at distribution levels as low as a few tenths of a microgram per square meter. Higher distribution levels may be required to control populations of other cockroach species such as the American cockroach (Periplaneta americana) and the oriental cockroach (Blatta orientalis). Also, in actual use in the field higher distribution levels than were used in the laboratory are used. Thus, depending on the nature of the surfaces in the habitat, the roach species, the mode of application etc., the distribution level of (S)-(+) hydroprene in actual use will conveniently be in the range of 0.3 mg/m2 to 40mg/m2, more preferably of 3 mg/m2 to 30 mg/m2.

(S)-(+) hydroprene is typically applied in composition form suitable for use in cockroach control.

Examples of compositions suitable for such use comprise aerosols (in aerosol dispensers or foggers), roach baits, roach dusts, emulsifiable concentrates, ready to use sprays, ultra low volume sprays, aroma disks, roach strips and the like; such compositions may be obtained in conventional manner. The composition of the invention is conveniently applied to cockroach habitats, which habitats include human lodgings, sites where food is stored or prepared and industrial facilities.

For use of (S) -(+) hydroprene in aerosol form, the active ingredient is conveniently formulated with an innocuous, volatile solvent and a propellant.

Examples of suitable volatile solvents are chlorinated alkanes such as methylene chloride or 1,1,1trichloroethane.

Examples of suitable propellants are low boiling alkanes such as propane or butane or fluorinated hydrocarbons.

For use of (S)-(+) hydroprene in spray form, e.g. as emulsifiable concentrate or ready to use spray, the active ingredient will conveniently be formulated with an emulsifying agent and a solvent.

Examples of suitable emulsifiers are sorbitol, fatty acid esters, polyethoxylated fatty acid esters of alcohols or phenols, calcium dodecyl benzoate and the like.

Examples of suitable solvents are aromatic hydrocarbons such as xylene.

Solid compositions such as dusts or powders comprise (S)-(+) hydroprene and a solid carrier.

Examples of suitable solid carriers are calcium carbonate, diatomaceous earth, clay and the like.

(S)-(+) hydroprene may also be applied in solid composition form by evaporation from a solid carrier, e.g. in the form of aroma disks and strips, particularly the latter.

Solid compositions such as aroma disks and strips will comprise (S)-(+) hydroprene, a polymer and, preferably a plasticizer.

Examples of suitable polymers (resins) are polyvinylchloride, polyethylene, polyurethane, polypropylene, acrylics, nylon, in particular polyvinylchloride.

For use of (S)-(+) hydroprene in bait form, the active ingredient will conveniently be formulated with a foodstuff.

Suitable foodstuffs for use in such baits are corn meal, dog food, corn syrup and the like.

(S)-(+) hydroprene may also be used in microencapsulated form. Such microcapsules are conveniently of the gelatin of nylon type; compositions comprising microcapsules contain conveniently a thickener such as xanthan gum.

The (S)-(+) hydroprene formulations of the invention may contain conventional additives such as U.V.

stabilizers, heat stabilizers, antioxidants, pigments etc. They may also contain conventional insecticides such as organophosphates and pyrethroidsto provide an initial knockdown of a portion ofthe cockroach population or other insects at the application site. They are prepared in a manner known per se. Suitable compositions of the invention comprise conveniently from 0.01 to 80% by weight of (S)-(+) hydroprene.

Conveniently aerosols will comprise from 0.01 to 10% by weight, emulsifiable concentrates and ultra low volume spray from 0.3 to 80% by weight, ready to use sprays from 0.5 to 10% by weight and roach baits or strips from 1 to 15% by weight of (S)-(+) hydroprene.

The invention is further illustrated by the following examples. These examples are not intended to limit the invention in any manner. Parts are by weight.

Formulation example 1. Aerosol A B C (S)-(+) hydroprene (100%) 0.021 0.064 0.1 CH2CI2 17.646 16.936 16.9 CCI3-CH3 54.333 55 55 propane/isobutane to 70 psi 28 28 28 2. Emulsifiable concentrate (S)-(+) hydroprene (100%) 10 antioxidant 0.2 (butylated hydroxytoluene) emulsifier 30.8 (polyoxyethylene sorbitol ester) solvent 59.0 (aliphatic hydrocarbon) 3. Ready to use spray (S)-(+) hydroprene (100%) 0.4 water 91.86 antioxidant 0.44 (butylated hydroxytoluene) emulsifier 2.0 (polyoxyethylene sorbitol ester) chelating agent (NaEDTA) 5.0 buffering agent (citric acid) 0.3 4. Bait (S)-(+) hydroprene (100) 1.0 CH2CI2 5.0 corn meal 94.0 5.Dust (S)-(+) hydroprene (100%) 10.0 Ethylene glycol 4.5 antioxydant (butylated hydroxy 0.5 toluene) silica 85 Test 1 Foggers comprising 15 mg and 45 mg of (S)-(+) hydroprene resp., formulated according to Formulation Examples 1A and 1 B resp. are discharged in an 85 m3 fogger chamber. At the time of discharge the chamber contained digarette papers and three different test substrates (treated vinyl tile, glass, and unpainted plywood) placed at distances of 1.8,2.7 and 3.7 m from the fogger. This mist is allowed to settle for 20 minutes and the papers and substrates are removed. The papers are extracted and the extracts analysed to determine the amount of (S)-(+) hydroprene (in Fg/cm2 substrate) deposited at the three distances. The depositions are in the range of 0.005 to 0.053 Fg/cm2.

After removal from the chamber the treated test substrates are placed in a laboratory under ambient conditions, Within one hour of removal, ten to twelve fifth to sixth instar German roaches are confined to each of the treated substrate surfaces. Food, water and harborage is supplied.

The containers are examined daily for the first ten days. At the examination times food and water are replenished as needed. All roaches molting to the adult stage are removed and destroyed during the first ten days of the test. (Roaches in the last ten days of the last instar before molt are not sensitive to juvenoids.) After day ten the containers are examined every seven to fourteen days and the following status information recorded.

Total number of surviving roaches.

Adult or nymph status of each roach.

Sex of all adult roaches.

JH effect on adult roaches if any.

Ootheca carried.

Viability of ootheca dropped.

F1 progeny produced.

The final reading is taken at week 12 after the ten-day post-treatment period.

Based on these readings the treatments are scored for overall juvenile hormone (JH) effects.

The overall JH response of (S) hydroprene was significantly better than the racemic mixture which was used as Standard. More importantly, the results of the readings on total F1 nymphs produced and F1 nymphs produced per female roach having the opportunity to mate and produce young indicate the reproduction control activity of (S)-(+) hydroprene was about 7-fold higher than the racemic mixture.

Test2 Seriai dilutions of (S)(+) hydroprene or racemic hydroprene in acetone are applied to glass and plywood plates by dribbling the solution onto the plates from a syringe. The plates are used as floors for test cages.

Each cage is supplied with harborage, water and food and 50 4th instar German cockroaches. The cages are maintained at 27"C, 16 hours light cycle, 50% relative humidity for about two months. Control efficacy is scored based on morphological effects and 100% inhibition of reproduction. In these tests (S)-(+) hydroprene provided 100% control reproduction. In these tests (S)-(+) hydroprene provided 100% inhibition of reproduction at a distribution of 0.1 Fg/cm2, whereas the lowest distribution giving 100% control with racemic hydroprene was 10 sg/cm2 on glass and 1 ,ug/cm2 on plywood.

Claims (11)

1. A pest controlling composition comprising a) (S)(+) hydroprene b) a diluent and c), where the diluent is a solvent, at least one adjuvant selected from a propellant, a surfactant and a thickener.

2. A composition according to Claim 1, comprising from 0.01 to 80% by weight of (S)-(+) hydroprene.

3. A composition according to Claims 1 or 2 in aerosol form.

4. A composition according to Claim 1 or 3 in spray form.

5. A composition according to Claim 1 or 2 in solid form.

6. A composition according to Claim 5 in bait form.

7. A composition according to Claim 5, wherein the diluent is a polymer and comprising additionally a plasticizer.

8. A method of controlling cockroaches comprising administering a cockroach reproduction inhibiting amount of (S)-(+) hydroprene to the locus infested by said population.

9. The method of Claim 8, wherein the distribution of (S)-(+) hydroprene to said locus is in the range of 0.3 to 40 mg/m2.

10. The method of Claim 8 or 9, wherein the (S)-(+) hydroprene is administered in aerosol or spray form.

11. The method of Claim 8 or 9, wherein the (S)-{+) hydroprene is administered by evaporation from a solid carrier.