Method of repelling insects

The present invention concerns methods and formulations for repelling insects, particularly for repelling mosquitoes and ticks.

Insect repellants are widely used throughout the United States and throughout the world. In some regions, the use of insect repellants is critical to avoiding or reducing the occurrence of disease carried by insects. For example the Centers for Disease Control (CDC) receives nearly 10,1000 reports of Lyme disease (transmitted by deer ticks) and 1,000 reports of encephalitis (transmitted by mosquitoes) annually).

Currently, the most common insect repellent is N,N-diethyl-meta-toluamide (DEET). DEET was designed to be applicable to the skin of subjects, and is designed to repel rather than kill insects. Although in use for some time, concern has recently emerged about the potential toxicity of DEET to children. Recently the US Environmental Protection Agency (EPA) determined that it would no longer allow child safety claims on labels for DEET-containing products.

The United States EPA Facts: Methyl Nonyl Ketone (July 1995) describes methyl nonyl ketone as a dog and cat repellent/training aid and iris borer deterrent, but does not suggest its use as an insect repellent.

U.S. Pat. No. 2,283,471 to Swaine describes the use of compounds such as methyl nonyl ketone and methyl undecyl ketone as contact insecticides for aphids and similar piercing-sucking insects (all primitive plant-feeding insects) which require contact insecticides for their control, but does not suggest their use as insect repellents.

R. Linderman et al., Pesticide Biochemistry and Physiology 35, 291-299 (1989), describes the inhibition of insect juvenile hormone esterase by α,β-unsaturated and α-acetylenic trifluoromethyl ketones, but does not suggest the use thereof as insect repellents.

Accordingly, there remains a need for new ways to repel insects, particularly mosquitoes and ticks.

Accordingly, the present invention provides a method of repelling an insect pest, comprising applying to a subject or substrate, in an amount effect to repel the insect pest, a compound of Formula I:

wherein R is C4-C20 linear or branched alkyl, preferably linear and preferably C7 to C13 alkyl.

Particularly preferred insects for application of the present method are mosquitoes, ticks and cockroaches.

Further aspects of the present invention include compositions comprising compounds of Formula (I), or other active compounds, in combination with carriers or other ingredients for repelling insects, and the use of compounds of Formula (I) or active compounds disclosed herein for the preparation of a composition for repelling insects.

As used herein, the term “alkyl” (e.g., alkyl, alkylcarboxy, alkylphenyl,etc.) refers to a straight or branched chain hydrocarbon having from 4 to 20 carbon atoms, which alkyl may be linear or branched. The alkyl may optionally be substituted with substituents selected from the group which includes halo, lower alkoxy, lower alkylsulfanyl, lower alkylsulfenyl, lower alkylsulfonyl, oxo, hydroxy, mercapto, amino optionally substituted by alkyl, carboxy, carbamoyl optionally substituted by alkyl, aminosulfonyl optionally substituted by a substituent selected from the group including alkyl, nitro, cyano, halo and lower perfluoroalkyl, multiple degrees of substitution being allowed. Examples of “alkyl” as used herein include, but are not limited to, n-butyl, n-pentyl, isobutyl, pentyl, hexyl, octyl, nonyl, undecyl, the like.

The term “loweralkoxy” as used herein means linear or branched Cl 1 to C 4 alkoxy, preferably methoxy, ethoxy, or propoxy.

The term “halo” as used herein means halogen, preferably fluoro, chloro, bromo or iodo, most preferably fluoro.

Subjects to be treated with compounds of the present invention include both human and animal subjects (e.g., dogs, cats, horses, cattle). Subjects may be directly or indirectly treated, such as by applying the active compound to the skin of the subject, or by applying the active compound to an article worn by or otherwise protecting the subject.

Substrates to be treated with compounds of the present invention include, but are not limited to, floors, plants, containers, walls, pools or open bodies of water, etc.

Insects that may be repelled by the methods of the present invention include ticks, fleas, cockroaches, and biting flies, typically of the order diptera, and further including mosquitoes, horse flies, deer flies, black flies, gnats, no-see ums, chiggers, etc.

The term “mosquito” as used herein concerns any type of mosquito (e.g., Anopheles, Aedes, and Culex), including but not limited to Tiger mosquitoes, Aedes aboriginis, Aedes Aegypti, Aedes, albopictus, Aedes cantator, Aedes sierrensis, Aedes sollicitans, Aedes squamiger, Aedes sticticus, Aedes vexans, Anopheles quadrimaculatus, Culex pipiens , and Culex quinquefaxciatus.

The term “tick” as used herein includes any type of tick, including but not limited to, deer ticks, the American dog tick ( Dermacentor variabilis ), Ornithodoros parkeri, O. moubata , and Dermacentor andersoni.

The term “cockroach” as used herein refers to any type of cockroach, including but not limited to the American cockroach ( Periplaneta americana ), German cockroach ( Blattella germanica ), oriental cockroach ( Blatta orientalis ), wood cockroach ( Parcoblatta pennsylvanica ), brownbanded cockroach ( Supella longipalpa ), and smokybrown cockroach ( Periplaneta fuliginosa ).

Other insect that can be treated by the methods of the present invention include, but are not limited to: lice (Order Phthiraptera), such as head and body lice of humans, Pediculus humanus capitis and P. H. humanus; Fleas (Order Siphonaptera), such as cat and dog fleas, Ctenocephalides sp. human fleas, Echidnophaga, Pulex sp. Bees, wasps and ants (Order Hymenoptera) mites such as Sarcoptes scabei (human itch mite) the North American chigger or red bug, Trombicula sp. nematodes such as human parasitic nematodes, Silverfish (Order Thysanura), such as Lepisma saccharina , firebrat, Thermobia domestica ; Termites (Order Isoptera) such as Reticulitermes flavipes, Incisitermes minor, Marginitermes hubbardi , and Cryptotermes brevis ; Earwigs (Order Dermaptera); Psocids (Order Psocoptera) such as booklice; Beetles (Order Coleoptera), particularly wood eating beetles; Centipedes such as Lithobius, Geophilus, Scutigera and millipides such as Julus terrestris ; Scorpions such as Centruroides sculpturatus and Mastigoproctus gianteus ; etc.

1. Repellant Compounds

Active compounds or compounds of Formula I herein are either known and may be produced in accordance with techniques known to those skilled in the art, or where novel may be produced by variations of known techniques which will be apparent to those skilled in the art.

2-tridecanone (methyl undecyl ketone) is commercially available from the Sigma-Aldrich Company, P.O. Box 2060, Milwaukee, Wis. 53201 USA as catalog number 17,283-9.

2-undecanone (methyl nonyl ketone) is commercially available from the Sigma-Aldrich Company, P.O. Box 2060, Milwaukee, Wis. 53201 USA as catalog number U-130-3.

2. Methods and Formulations for Repelling Insects

The present invention provides repellant compounds, compositions comprising aid repellant compounds and the use of such repellant compounds and compositions n controlling pests, particularly insect pests such as mosquitoes.

Liquid formulations may be aqueous-based or non-aqueous (i.e., organic olvents), or combinations thereof, and may be employed as foams, gels, suspensions, emulsions, microemulsions or emulsifiable concentrates or the like. The ingredients may include rheological agents, surfactants, emulsifiers, dispersants or polymers.

In one embodiment, a floor wax composition may include repellant compounds as described herein, in an amount effective to repel cockroaches that might otherwise feed upon the composition once applied to floors, or to simply repel cockroaches from floor surfaces to which they are applied.

As will be appreciated by a person skilled in the art, the repellant concentration will vary widely depending upon the nature of the particular formulation, particularly whether it is a concentrate or to be used directly. The repellant compound will be present in the composition in a concentration of at least about 0.0001% by weight and may be 10, 50, 99 or 100% by weight of the total composition. The repellant carrier may be from 0.1% to 99.9999% by weight of the total composition. The dry formulations will have from about 0.0001-95% by weight of the pesticide while the liquid formulations will generally have from about 0.0001-60% by weight of the solids in the liquid phase.

The formulations may be applied to the subject's skin, or may be applied to garments, belts, collars, or other articles worn by the subject from whom insects are to be repelled. The formulation may be applied to netting or screening that protects a subject, particularly a sleeping subject. The formulations may be applied to non-animal substrates from which insects are to be repelled, such as plants. Application to subjects or substrates may be carried out by spraying, dusting, sprinkling or the like.

The compounds according to the present invention may be employed alone or in mixtures with one another and/or with such solid and/or liquid dispersible carrier vehicles as described herein or as otherwise known in the art, and/or with other known compatible active agents, including, for example, insecticides, acaricides, rodenticides, fungicides, bactericides, nematocides, herbicides, fertilizers, growth-regulating agents, etc., if desired, in the form of particular dosage preparations for specific application made therefrom, such as solutions, emulsions, suspensions, powders, pastes, and granules as described herein or as otherwise known in the art which are thus ready for use.

The repellant compounds may be administered with other insect control chemicals, for example, the compositions of the invention may employ various chemicals that affect insect behavior, such as insecticides, attractants and/or repellents, or as otherwise known in the art. The repellant compounds may also be administered with chemosterilants.

The repellant compounds are suitably applied by any method known in the art including, for example, spraying, pouring, dipping, in the form of concentrated liquids, solutions, suspensions, sprays, powders, pellets, briquettes, bricks and the like, formulated to deliver a repellant effective concentration of the repellant compound. The repellant formulations may be applied in a repellant effective amount to an area of pest infestation or an area susceptible to infestation, a body of water or container, a barn, a carpet, pet bedding, an animal, clothing, skin, and the like.

The following examples are illustrative of the practice of the present invention, and should not be construed as limiting thereof. All percentages are by weight and all solvent mixture proportions are by volume unless otherwise noted.