EP3962274A1 - Use of volatile organic compounds as molluscides - Google Patents

Abstract

The present invention relates to Use of 3-octanone, 1-octen-3-ol or a mixture thereof as a molluscicide.

Description

Use of volatile organic compounds as molluscides

INTRODUCTION

The present invention relates to use of 3-octanone, 1-octen-3-ol or a mixture thereof as a molluscicide. The invention also relates to a method of controlling molluscs, comprising applying an effective amount of 3-octanone, 1-octen-3-ol or a mixture thereof.

BACKGROUND

Snails and slugs are serious pests of agricultural, horticultural and aquatic plants. They cause feeding damage to both aerial and subterranean parts of the plant, including leaves, shoots, roots, tubers, corms, bulbs, flowers and seeds. Besides reducing plant stand and crop yield they increase the risk of infection by opportunistic plant pathogens. Feeding damage can significantly reduce the aesthetic appearance of plants (e.g. nursery stock, root crops, salads) and hence their marketability.

Slug and snail population densities have increased over the years due to changes in crop management such as minimum tillage, direct drilling, and over wintering arable crops. Their pest status is set to increase further due to legislative changes to pesticide usage and climate change with weather patterns favouring their population growth. The problem is often exacerbated by the accidental introduction of highly damaging invasive mollusc species, e.g. the Golden Apple Snails ( Pomacea canaliculate, Pomacea maculate), which have devastated rice crops in Asia.

Current mollusc control is still heavily dependent upon the use of chemical pesticides such as metaldehyde, ferric phosphate, methiocarb and thiodicarb. Metaldehyde-based products by far dominate the molluscicide bait market worldwide but have corresponding ecotoxicological effects on non-target species including beneficial insects and can lead to contamination of drinking water. However, metaldehyde will be withdrawn in the UK by 2020 as it was assessed by Government experts as posing an“unacceptable risk to birds and small mammals”.

Non-chemical and low environmental impact methods including, e.g. physical barriers, plant-derived natural products, application of predators such as beetles, or exposure to parasites such as nematodes, have also been suggested as methods of controlling gastropod pests. To date, however, none of these methods have been as effective or as convenient as chemicals. SUMMARY OF THE INVENTION

Viewed from a first aspect, the present invention provides the use of 3- octanone, 1-octen-3-ol or a mixture thereof as a molluscicide.

Viewed from a further aspect, the present invention provides a method of controlling molluscs, comprising applying an effective amount of 3-octanone, 1-octen-3- ol or mixture thereof, to an area requiring mollusc control.

DEFINTIONS

As used herein, the term“pesticide” refers to any natural, synthetic or semi synthetic substance that may be used to control (e.g. inhibit the growth of, repel and/or kill) unwanted organisms (pests) such as plants, insects, animals, fungi, molluscs, arthropods, larvae, nematodes, microorganisms and algae.

As used herein, the term“molluscicide” refers to any natural, synthetic or semi synthetic substance that may be used to control (e.g. inhibit the growth of, repel and/or kill) molluscs.

As used herein, the term“molluscs” refers to any invertebrate that belongs to the phylum Mollusca.

As used herein, the term“gastropods” refers to any invertebrate that belongs to the Gastropoda class of molluscs. Gastropods typically have a flattened muscular foot for locomotion and a head bearing stalked eyes.

As used herein, the term“composition” refers to an administrable or useable form. Compositions often include additional ingredients other than the active ingredients, e.g. molluscicide, to improve the properties of the composition e.g. to make the composition more stable and/or easier to handle, store and/or apply. As used herein,“solid compositions” are compositions that are solid (i.e. not liquid or gaseous) at 20 °C and atmospheric pressure. As used herein “liquid compositions” are compositions that are liquid (i.e. not solid or gaseous) at 20 °C and atmospheric pressure. As used herein“slurry compositions” are fluid mixtures of a solid with a liquid at 20 °C and atmospheric pressure.

As used herein, the term “active ingredient” refers to a compound within a composition that is biologically or chemically active against the target organisms, i.e. molluscs.

As used herein, the term “volatile organic compound” (“VOC”) refers to an organic chemical compound (i.e. a compound containing carbon and hydrogen atoms and optionally containing heteroatoms such as oxygen, sulphur, halogens and nitrogen) which has a high vapour pressure at atmospheric pressure and room temperature. Typically a VOC will have a boiling point of less than or equal to 250 °C, when measured at standard atmospheric pressure.

As used herein, the term “fumigant” refers to a pesticide, or a composition comprising a pesticide, which exists in, or can be transformed into, gaseous form when it is used to control pests.

As used herein, the term“fumigation” refers to a method of pest control that uses a gaseous pesticide to control pests.

As used herein, the term“plant propagation material” refers to all the generative parts of the plant and includes seeds, roots, fruits, tubers, bulbs, rhizomes, shoots, sprouts. It also includes seedlings.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof as a molluscicide. 3-Octanone and 1-octen-3-ol are both naturally occurring, volatile organic compounds (VOCs), produced by the entomopathogenic fungus Metarhizium brunneum. The compounds are potent molluscicides and exhibit, for example, much higher molluscicidal activity than 1-octene.

Advantageously 3-octanone and 1-octen-3-ol are much safer, with a better environmental profile, than many“chemical” molluscicides currently available. Both 3- octanone and 1-octen-3-ol are naturally occurring, and since they are both volatile they do not leave any residues in the environment. They also do not impact on non-target species, e.g. agricultural animals or domestic animals or beneficial insects.

In some preferred uses of the present invention, 3-octanone is the molluscicide. In other preferred uses of the present invention, 1-octen-3-ol is the molluscicide. Alternatively a mixture of 3-octanone and 1-octen-3-ol may be used as the molluscicide. When a mixture is used, 3-octanone and 1-octen-3-ol may be used separately, sequentially and/or in combination, e.g. in a mixture.

In preferred uses of the present invention, the 3-octanone, 1-octen-3-ol or a mixture thereof repels molluscs. Thus, for example, if 3-octanone, 1-octen-3-ol or a mixture thereof is applied to an area the presence of 3-octanone, 1-octen-3-ol or a mixture thereof causes any molluscs present therein to leave and/or prevents or inhibits further molluscs entering the area. In other preferred uses of the present invention, the 3-octanone, 1-octen-3-ol or a mixture thereof kills molluscs. Thus, for example, if an area such as a cloche or greenhouse is infested with molluscs, 3-octanone, 1-octen-3-ol or a mixture thereof can be applied and the exposure (e.g. contact) of the molluscs with the 3-octanone, 1- octen-3-ol or a mixture thereof will kill them.

In some preferred uses of the present invention, a further active ingredient is used. Thus optionally the invention provides use of 3-octanone, 1-octen-3-ol or a mixture thereof, and a further active ingredient, as a molluscicide. The 3-octanone, 1- octen-3-ol or mixture thereof, and the further active ingredient may be used separately, sequentially and/or in combination, i.e. in a mixture. One or more further active ingredients may be used.

Preferably the further active ingredient is a pesticide. The 3-octanone, 1-octen- 3-ol or a mixture thereof may be used separately, sequentially and/or in combination with multiple (e.g. 2, 3 or 4) further pesticides. Preferably, the further pesticide is selected from herbicides, molluscicides, insecticides, fungicides, algaecides, rodenticides, nematicides, acaricides, larvicides and mixtures thereof. In some preferred uses of the invention, the further pesticide is a pesticide other than a molluscicide, i.e. it is selected from herbicides, insecticides, fungicides, algaecides, rodenticides, nematicides, acaricides, larvicides and mixtures thereof . This enables the control of multiple different kinds of pest in a single process, with the 3-octanone, 1- octen-3-ol or a mixture thereof providing sufficient mollusc control and the further pesticide(s) providing complementary control of one or more different kinds of pest.

Preferred herbicides for use as a further active ingredient in the present invention are selected from isoproturon, norflurazon, fluridone, paraquat, simazine, glyphosphate, terbuthylazine, cyhalofop-butyl, penoxsulam, bensulfuron-methyl, azimsulfuron, imazosulfuron, fenoxaprop-P-ethyl, 2,4-D, acetochlor, acifluorfen, alachlor, amidosulfuron, aminopyralid, aminotriazole, ammonium thiocyanate, anilifos, benfuresate, bentazon, benthiocarb, benzobicyclon, benzofenap, bifenox, bromobutide, butachlor, cafenstrole, carfentrazone, chlorimuron, chlorpropham, clomazone, clomeprop, clopyralid, cumyluron, daimuron, diclofop, diflufenican, dimepiperate, dimethametryn, diquat, dithiopyr, EK2612, EPTC, esprocarb, ET-751 , ethbenzanid, fenoxaprop-ethyl, isoxidifen-ethyl, fenoxasulfone, fentrazamide, flazasulfuron, flufenacet, flufenpyr, flumioxazin, flupyrsulfuron, fluroxypyr, fomesafen, foramsulfuron, glufosinate, glyphosate, imazamethabenz, imazapic, imazapyr, imazaquin, indanofan, indaziflam, ioxynil, ipfencarbazone, isoxaben, MCPA, MCPB, mefenacet, mesosulfuron, mesotrione, metolachlor, molinate, monosulfuron, MSMA, orthosulfamuron, oryzalin, oxadiargyl, oxadiazon, oxazichlomefone, oxyfluorfen, paraquat, pendimethalin, pentoxazone, pethoxamid, picloram, pinoxaden, piperophos, pretilachlor, prohexadione, propachlor, propanil, propisochlor, propyzamide, prosulfocarb, prosulfuron, pyributicarb, pyraclonil, pyrazogyl, pyrazolynate, pyrazoxyfen, pyridate, quinoclamine, quinclorac, S-3252, saflufenacil, simazine, simetryne, s-metolachlor, sulcotrione, sulfentrazone, sulfosate, tefuryltrione, tepraloxydim, thenylchlor, thiazopyr, thiobencarb, triclopyr, trifluralin, trinexapac, tritosulfuron and mixtures thereof, preferably isoproturon, norflurazon, fluridone, paraquat and simazine.

Preferred insecticides for use as a further active ingredient in the present invention are selected from chlorpyrifos, carbofuran, fibronil, abamectin, acephate, acetamiprid, acrinathrin, cypermethrin, endosulfan, azadirachtin, azinphos-ethyl, azinphos-methyl, bendiocarb, benfuracarb, bensultap, cyfluthrin, cypermethrin, bifenthrin, bufencarb, buprofezin, butacarb, cadusafos, carbaryl, carbofuran, carbosulfan, cartap, cartap hydrochloride, chlorantraniliprole, chlorfenapyr, chlorfenvinphos, chlorfluazuron, chlormephos, chlorpyrifos, chlorpyrifos-methyl, chromafenozide, clothianidin, cyantraniliprole, cyfluthrin, cyhalothrin, cypermethrin, deltamethrin, diazinon, dicrotophos, diflubenzuron, dimethoate dinotefuran, disulfoton, emamectin, emamectin benzoate, endosulfan, endothion, endrin, EPN, esfenvalerate, etaphos, ethiofencarb, ethion, ethiprole, ethoate-methyl, etofenprox, fenamiphos, fenazafior, fenethacarb, fenitrothion, fenobucarb, fenpropathrin, fensulfothion, fenthion, fenthion-ethyl, fenvalerate, fipronil, flonicamid, flubendiamide, flucythrinate, fonofos, fufenozide, furathiocarb, gamma- cyhalothrin, gamma-RCR, halfenprox, halofenozide, heptenophos, hyquincarb, imidacloprid, indoxacarb, isazofos, isobenzan, isocarbophos, isofenphos, isofenphos-methyl, isoprocarb, isothioate, isoxathion, kinoprene, cyhalothrin, lepimectin, lufenuron, malathion, methamidophos, methomyl, methoxyfenozide, mevinphos, mexacarbate, milbemectin, monocrotophos, nitenpyram, novaluron, omethoate, oxamyl, oxydemeton-methyl, oxydeprofos, oxydisulfoton, parathion, parathion-methyl, penfluron, permethrin, phenthoate, phorate, phosalone, phosfolan, phosmet, phosphamidon, pirimetaphos, pirimicarb, pirimiphos-ethyl, pirimiphos-methyl, primidophos, profenofos, profluthrin, promecarb, propaphos, propoxur, prothiofos, pymetrozine, pyrafluprole, pyridalyl, pyrifluquinazon, pyriprole, pyriproxyfen, spinetoram, spinosad, spirotetramat, sulfoxaflor, sulprofos, tau- fluvalinate, tebufenozide, tebufenpyrad, teflubenzuron, tefluthrin, tetramethylfluthrin, theta-cypermethrin, thiacloprid, thiamethoxam, thicrofos, thiocyclam, thiocyclam oxalate, thiodicarb, thiometon, thiosultap, thiosultap-disodium, thiosultap-monosodium, thuringiensin, tolfenpyrad, triazophos, triflumuron, zeta-cypermethrin and mixtures thereof, preferably chlorpyrifos, carbofuran and fibronil.

Preferred fungicides for use as a further active ingredient in the present invention are selected from tricyclazole, phthalide, carpropamide, pyroquilon, diclocymet, fenoxanil, probenazole, isoprothiolane, iprobenfos, isotianil, tiadinil, kasugamycin, flutolanil, mepronil, pencycuron, polyoxins, validamycin, toclophos- methyl, boscalid, penthiopyrad, thifluzamide, bixafen, fluopyram, isopyrazam, propiconazole, difenoconazole, fenbuconazole, ipconazole, silthiofam, triadimefon, hexaconazole, azoxystrobin, metaminostrobin, orysastrobin, acibenzolar-S-methyl and mixtures thereof.

Preferred algaecides for use as a further active ingredient in the present invention are selected from benzalkonium chloride, bethoxazin, copper sulfate, cybutryne, dichlone, dichlorophen, diuron, endothal, fentin, hydrated lime, isoproturon, methabenzthiazuron, nabam, oxyfluorfen, pentachlorophenyl laurate, quinoclamine, quinonamid, simazine terbutryn and mixtures thereof.

Preferred rodenticides for use as a further active ingredient in the present invention are selected from warfarin, chlorphacinone, diphacinone, bromadiolone, difethialone, brodifacoum, bromethalin, cholecalciferol, zinc phosphide, strychnine and mixtures thereof.

Preferred acaricides for use as a further active ingredient in the present invention are selected from permethrin, ivermectin, dicofol, abamectin, acequinocyl, bifenazate, chlorpenafyr, clofentezine, cyflumetofen, cypermethrin, dicofol, etoxazole, fenazaquin, fenpyroximate, hexythiazox, imidacloprid, propargite, pyridaben, spiromesifen, spirotetramat and mixtures thereof.

Preferred larvicides for use as a further active ingredient in the present invention are selected from bifenthrin, carbofuran, chlorpyrifos, cyfluthrin, phostebupirim, diazinon, ethoprop, fipronil, imidacloprid, lindane, permethrin, phorate, terbufos, captan, carboxin, maneb, metalaxyl, thiamethoxam and mixtures thereof.

In more preferred uses of the invention, the further pesticide is a molluscicide. Thus preferably the present invention provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, and a further active ingredient, as a molluscicide, wherein the further active ingredient is a different molluscicide. Optionally the 3-octanone, 1-octen-3-ol or a mixture thereof, and the different molluscicide, is used separately, sequentially and/or in combination, i.e. in a mixture. The use of a further molluscicide may advantageously contribute to a higher level of mollusc control and/or a longer lasting molluscicidal effect. It may, for example, be beneficial to employ a further molluscicide having a lower volatility than the 3-octanone and/or 1-octen-3-ol or having other complementary properties. Preferred further molluscicides (i.e. further active ingredients) for use in the present invention are selected from metaldehyde, copper sulfate, kainite, phenol pentabromide, sodium pentachlorophenolate, 2,4,6-triiodophenol, 2,4,6- tribromophenol, niclosamide, copper dimethyl dithiocarbamate, 2,4-dinitro creosol, allicin, bromoacetamide, calcium arsenate, cloethocarb, fentin, ferric phosphate, methiocarb, niclosamide, Paris green, pentachlorophenol, sodium pentachlorophenate, tazimcarb, thiacloprid, thiodicarb, tralopyril, tributyltin oxide, trifenmorph, trimethacarb and mixtures thereof. Metaldehyde is preferred.

In some preferred uses of the present invention, however, no further (i.e. no additional) molluscicides are used, i.e. no molluscicide other than the 3-octanone, 1- octen-3-ol or a mixture thereof, is used. This advantageously avoids the use of substances which may have harmful effects, e.g. in terms of toxicity and/or environmental impact, or may be difficult or expensive to obtain or use. The use is also simpler as complex combinations, applications and sequences of various molluscicides are avoided, whilst still achieving the desired molluscicidal effect. In such uses the molluscicidal effect is thus achieved solely by the 3-octanone, 1-octen-3-ol or a mixture thereof, which have the desirable properties described above. Thus in a preferred use the invention provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein no further molluscicides are used. Thus the invention preferably provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein the 3-octanone, 1-octen-3-ol or a mixture thereof is the sole molluscicide.

Particularly preferably, no further (i.e. no additional) pesticides are used in the present invention, i.e. no pesticide other than the 3-octanone, 1-octen-3-ol or a mixture thereof, is used. In such uses the pesticidal effect is thus achieved solely by the 3- octanone, 1-octen-3-ol or a mixture thereof, which have the desirable properties described above and undesirable effects of further pesticides are avoided. The use is also simpler as complex combinations, applications and sequences of various pesticides are avoided, whilst still achieving the desired pesticidal, e.g. molluscicidal, effect. Thus in a preferred use the invention provides the use of 3-octanone, 1-octen-3- ol or a mixture thereof, as a molluscicide, wherein no further pesticides are used. Thus the invention preferably provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein the 3-octanone, 1-octen-3-ol or a mixture thereof is the sole pesticide.

Especially preferably, no further (i.e. no additional) active ingredients are used in the present invention, i.e. no active ingredient other than the 3-octanone, 1-octen-3- ol or a mixture thereof, is used. In such uses the active effect is thus achieved solely by the 3-octanone, 1-octen-3-ol or a mixture thereof, which have the desirable properties described above and undesirable effects of further active ingredients are avoided. The use is also simpler as complex combinations, applications and sequences of various active ingredients are avoided, whilst still achieving the desired molluscicidal effect. Thus in a preferred use the invention provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein no further active ingredients are used. Thus the invention preferably provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein the 3-octanone, 1-octen-3-ol or a mixture thereof is the sole active ingredient.

In some preferred uses of the present invention, no further (i.e. no additional) volatile organic compounds (VOCs) are used, i.e. no VOC other than the 3-octanone, 1-octen-3-ol or a mixture thereof, is used. Thus in a preferred use the invention provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein no further volatile organic compounds are used. Thus the invention preferably provides the use of 3-octanone, 1-octen-3-ol or a mixture thereof, as a molluscicide, wherein the 3-octanone, 1-octen-3-ol or a mixture thereof is the sole volatile organic compound.

In particularly preferred uses of the present invention, the 3-octanone, 1-octen- 3-ol or a mixture thereof is used in the form of a composition, wherein said composition comprises one or more additional ingredients. The one or more additional ingredients may comprise one or more of the further active ingredients described above (e.g. one or more of the further pesticides and/or one or more of the further molluscicides). Additionally or alternatively, the one or more additional ingredients may comprise one or more non-active ingredients. These ingredients are conventionally present in pesticidal compositions. Typically the type of non-active ingredient(s) present depends on the form of the composition.

In uses of the present invention, wherein the 3-octanone, 1-octen-3-ol or a mixture thereof is used in the form of a composition, the composition may take any conventional form. Preferably the composition is selected from a solid composition, a liquid composition and a slurry composition and more preferably a solid composition or a liquid composition. In one preferred use of the present invention, the composition is a solid composition. The solid composition is preferably in the form of pellets, granules (e.g. emulsifiable granules, water dispersible granules or granules for broadcast application), powders (e.g. wettable powders, soluble powders), briquettes, blocks, dusts, paste, gels, pressings, capsules or mixtures thereof. Pellets and granules are particularly preferred. In another preferred use, the composition is a liquid composition. The liquid composition is preferably in the form of a solution, an emulsion, an emulsifiable concentrate, a suspension or an ultra-low volume concentrate. In a further preferred use, the composition is a slurry composition. The compositions may be prepared by conventional techniques, well known to the person skilled in the art of agrichemical product formulation.

The one or more additional ingredients may be selected from solvents, diluents, carriers, fillers, bulking agents, surfactants, adjuvants, thickeners, lubricants, anti freezing agents, antifoaming agents, disintegrants, wetting agents buffers, pH modifiers, antioxidants, biostimulants, preservatives (e.g. mould inhibitors), binding agents, bait substances, bird deterrents (e.g. dyes), animal repellents, and mixtures thereof. Preferably the one or more additional ingredients are selected from solvents, diluents, carriers and/or surfactants.

Representative examples of suitable solvents and diluents include water and organic solvents. Organic solvents include mineral oil fractions of medium to high boiling point, (e.g. kerosene, diesel oil, oils of vegetable or animal origin), aliphatic, cyclic and aromatic hydrocarbons, (e.g. toluene, paraffin, tetrahydronaphthalene, alkylated naphthalenes), alcohols, (e.g. ethanol, propanol, butanol, benzyl alcohol, cyclohexanol) glycols, DMSO, ketones, (e.g. cyclohexanone), esters, (e.g. lactates, carbonates, fatty acid esters, gamma-butyrolactone), fatty acids, phosphonates, amines, amides, (e.g. N-methyl pyrrolidone) and mixtures thereof.

Representative examples of suitable carriers include mineral earths, (e.g. silicates, silica gels, talc, kaolins, limestone, lime, chalk, clays, dolomite, diatomaceous earth, bentonite, calcium sulfate, magnesium sulfate, magnesium oxide), polysaccharides, (e.g. cellulose, starch), cyclodextrins, microcrystalline cellulose, fertilizers, (e.g. ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas), products of vegetable origin, (e.g. cereal meal, tree bark meal, wood meal, nutshell meal) and mixtures thereof. Microcrystalline cellulose is a particularly preferred carrier.

Suitable surfactants include anionic, cationic, nonionic and amphoteric surfactants. Surfactants may be used as an emulsifier, dispersant, solubilizer, wetter, penetration enhancer, protective colloid, and/or adjuvant. Representative examples of suitable anionic surfactants include alkali, alkaline earth or ammonium salts of sulfonates, sulfates, phosphates, carboxylates, and mixtures thereof. Examples of sulfonates are alkylaryl sulfonates, diphenyl sulfonates, alpha-olefin sulfonates, lignin sulfonates, sulfonates of fatty acids and oils, sulfonates of ethoxylated alkylphenols, sulfonates of alkoxylated arylphenols, sulfonates of condensed naphthalenes, sulfonates of dodecyl- and tridecylbenzenes, sulfonates of naphthalenes and alkyl naphthalenes, sulfosuccinates or sulfosuccinamates. Examples of sulfates are sulfates of fatty acids and oils, of ethoxylated alkylphenols, of alcohols, of ethoxylated alcohols, or of fatty acid esters. Examples of phosphates are phosphate esters. Examples of carboxylates are alkyl carboxylates, and carboxylated alcohol or alkylphenol ethoxylates.

Representative examples of suitable nonionic surfactants are alkoxylates, N- substituted fatty acid amides, amine oxides, esters, sugar-based surfactants, polymeric surfactants, and mixtures thereof. Examples of alkoxylates are compounds such as alcohols, alkylphenols, amines, amides, arylphenols, fatty acids or fatty acid esters which have been alkoxylated with 1 to 50 equivalents. Ethylene oxide and/or propylene oxide may be employed for the alkoxylation, preferably ethylene oxide. Examples of N- substituted fatty acid amides are fatty acid glucamides or fatty acid alkanolamides. Examples of esters are fatty acid esters, glycerol esters or monoglycerides. Examples of sugar-based surfactants are sorbitans, ethoxylated sorbitans, sucrose and glucose esters or alkylpolyglucosides. Examples of polymeric surfactants are home- or copolymers of vinyl pyrrolidone, vinyl alcohols, or vinyl acetate. Suitable cationic surfactants are quaternary surfactants, for example quaternary ammonium compounds with one or two hydrophobic groups, or salts of long-chain primary amines.

Representative examples of suitable amphoteric surfactants include alkylbetains and imidazolines.

Representative examples of suitable thickeners are polysaccharides (e.g. xanthan gum, carboxymethyl cellulose), inorganic clays (organically modified or unmodified), polycarboxylates, and silicates).

Any conventional lubricants, anti-freezing agents, antifoaming agents, disintegrants, buffers, pH modifiers, antioxidants, biostimulants, preservatives (e.g. mould inhibitors), binding agents, bait substances, bird deterrents (e.g. dyes), animal repellents may be used. The compositions of the present invention preferably comprise 0.1-100 %wt, preferably 1-20 %wt, more preferably 2-10 %wt, and still more preferably 2-8 %wt, of 3- octanone, 1-octen-3-ol or a mixture thereof.

The compositions of the present invention preferably comprise 0.1-100 %wt, preferably 1-20 %wt, more preferably 2-10 %wt, and still more preferably 2-8 %wt, of active substances (i.e. 3-octanone, 1-octen-3-ol or a mixture thereof and any additional further active ingredients present).

The compositions of the present invention may be provided in ready-to-use form or as a concentrate. Solid compositions are preferably provided in ready-to-use form. Liquid and slurry compositions are preferably provided in the form of a concentrate. Instructions for dilution of the composition are preferably provided.

In preferred uses of the present invention, the 3-octanone, 1-octen-3-ol or a mixture thereof, or compositions comprising 3-octanone, 1-octen-3-ol or a mixture thereof, may be applied prior to, during or after sowing of the plants. The methods for applying the 3-octanone, 1-octen-3-ol or a mixture thereof, or compositions comprising 3-octanone, 1-octen-3-ol or a mixture thereof, include pelleting and spraying. Other conventional methods may also be used.

In uses of the present invention, the 3-octanone, 1-octen-3-ol or mixture thereof may protect the plant per se, plant propagation material, or soil or water in which the plants are growing. The 3-octanone, 1-octen-3-ol or a mixture thereof protects against attack or infestation by molluscs, e.g. gastropods. In use, the 3-octanone, 1-octen-3-ol or a mixture thereof may be applied to the plant or plant propagation material, to the molluscs directly, or may be applied to their habitat or breeding ground of the molluscs.

The amounts of 3-octanone, 1-octen-3-ol or mixture thereof, depend inter alia on the area of application, the prevalence of mollusc, the weather, duration of effect, mode of application and the kind of effect desired. Typically, however, 3-octanone, 1- octen-3-ol or mixture thereof is applied in an amount of 0.001-50.00 g Al/m², more preferably 0.01-5.00 Al/m² and still more preferably 0.1 -0.5 g Al/m² (wherein Al refers to active ingredient). When used in the form of a solid composition, the amount of 3- octanone, 1-octen-3-ol or mixture thereof applied is preferably 0.001-50.00 g Al/m², more preferably 0.1-5.00 g Al/m² and still more preferably 0.1 -0.5 g Al/m². When used in the form of a liquid composition, the amount of 3-octanone, 1-octen-3-ol or mixture thereof applied is preferably 0.001-50.00 g Al/m², more preferably 0.01-5.00 g Al/m² and still more preferably 0.1 -0.5 g Al/m². When used in the protection of stored products, the amount of 3-octanone, 1- octen-3-ol or mixture thereof applied depends, inter alia, on the application area (e.g. its surface area and density) and on the desired effect. Typical amounts applied for protection during storage are 0.1-3600 g Al/tonne bulk product, preferably 1-360 g Al/tonne bulk product and more preferably 12-36 g Al/tonne of bulk product of 3- octanone, 1-octen-3-ol or mixture thereof per cubic meter of stored product.

Preferably the present invention provides the use of 3-octanone, 1-octen-3-ol or mixture thereof as a molluscicide to control any type of mollusc. Examples of molluscs include gastropods, bivalves and cephalopods. However, in more preferred uses, the present invention provides the use of 3-octanone, 1-octen-3-ol or mixture thereof as a molluscicide to control gastropods. Representative examples of gastropods include snails, slugs, whelks and limpets. Particularly preferably the present invention provides the use of 3-octanone, 1-octen-3-ol or mixture thereof as a molluscicide to control slugs and/or snails. The slugs and snails may be land-based or aquatic.

Preferably the slugs and snails are selected from Achatina spp., Agriolimax spp., Arion spp. (e.g. A. ater, A. circumscriptus, A. distinctus, A. fasciatus, A. hortensis, A. intermedius, A. rufus, A. subfuscus, A. silvaticus, A. lusitanicus), Biomphalaria spp., Bradybaena spp. (e.g. B. fruticum), Bulinus spp., Cantareus spp. (e.g. C. asperses), Cepaea spp. (e.g. C. hortensis, C. nemoralis), Cernuella spp., Cochlicella spp., Cochlodina spp. (e.g. C. laminata), Deroceras spp. (e.g. D. agrestis, D. empihcorum, D. laeve, D. panornimatum, D. reticulatum), Discus spp. (e.g. D. rotundatus), Euomphalia spp., Galba spp. (e.g. G. trunculata), Helicella spp. (e.g. H. itala, H. obvia), Helicigona spp. (e.g. H. arbustorum), Helicodiscus spp., Helix spp. (e.g. H. aperta, H. aspersa, H. pomatia), Limax spp. (e.g. L cinereoniger, L. flavus, L marginatus, L maximus, L tenellus), Lymnaea spp. (e.g. L. stagnalis), Milax spp. (e.g. M. gagates, M. marginatus, M. sowerbyi, M. budapestensis), Oncomelania spp., Opeas spp., Oxyloma spp. (e.g. O. pfeifferi), Pomacea spp. (e.g. P. canaliculata), Succinea spp., Tandonia spp. (e.g. T. budapestensis, T. sowerbyi), Theba spp., Vallonia spp., and Zonitoides spp. (e.g. Z. nitidus).

Preferably the present invention provides the use of 3-octanone, 1-octen-3-ol or mixture thereof, as a molluscicide to treat any area, surface or space requiring mollusc control. Preferably, however, the present invention provides the use of 3-octanone, 1- octen-3-ol or mixture thereof, as a molluscicide to treat plants, plant propagation material, the soil or water in which plants are growing or stored plant produce. The use may be preventative, treating or a combination thereof. In one preferred use the present invention provides the use of 3-octanone, 1- octen-3-ol or mixture thereof, as a molluscicide to treat plants. Representative examples of plants include cereals, (e.g. durum and other wheat, rye, barley, triticale, oats, rice, or maize (fodder maize and sugar maize/sweet and field corn)), beet, (e.g. sugar beet or fodder beet), fruits, (e.g. pomes, stone fruits or soft fruits including apples, pears, plums, peaches, nectarines, almonds, cherries, papayas, strawberries, raspberries, blackberries or gooseberries), banana, vines (e.g. table grapes and grape juice grape vines), leguminous plants (e.g. beans, lentils, peas, alfalfa or soybeans), oil plants (e.g. rapeseed (oilseed rape), turnip rape, mustard, olives, sunflowers, coconut, cocoa beans, castor oil plants, oil palms, ground nuts or soybeans, cucurbits (e.g. squashes, pumpkins, cucumber or melons, fiber plants (e.g. cotton, flax, hemp or jute), citrus fruit (e.g. oranges, lemons, grapefruits or mandarins), vegetables (e.g. eggplant, spinach, lettuce (e.g. iceberg lettuce), chicory, cabbage, asparagus, cabbages, carrots, onions, garlic, leeks, tomatoes, potatoes, cucurbits or sweet peppers, lauraceous plants, (e.g. avocados, cinnamon or camphor), tobacco, nuts (e.g. walnuts), pistachios, coffee, tea, hop, sweet leaf, natural rubber plants, ornamental and forestry plants (e.g. flowers including carnation, petunias, geranium/pelargoniums, pansies and impatiens), shrubs, broad-leaved trees (e.g. poplar), evergreens, (e.g. conifers), eucalyptus, turf, lawn, grass such as grass for animal feed or ornamental uses. Preferred plants include potatoes sugar beets, tobacco, wheat, rye, barley, oats, rice, corn, cotton, soybeans, rapeseed, legumes, sunflowers, coffee, sugar cane, fruits, vines, ornamentals, and vegetables (e.g. cucumbers, tomatoes, beans or squashes).

Particularly preferred plants are selected from cereals, vegetables, fruits, oil crops, tobacco, and ornamental plants. Preferred cereals include wheat, barley, maize and rice. Preferred vegetables include leaf vegetables, bud vegetables, tuber vegetables, root vegetables, leguminous vegetables, and stem shoot vegetables. Representative examples of preferred vegetables include lettuce, spinach, cabbage, Brussels sprout, potatoes, sugar beets, radishes, carrots, beans, peas, and asparagus. Preferred fruits are strawberries. Preferred oil crops include rapeseed.

In another preferred use the present invention provides the use of 3-octanone, 1-octen-3-ol or mixture thereof, as a molluscicide to treat stored plant produce. Preferably the stored plant produce is a plant as described above.

Another preferred use of the present invention is the use of 3-octanone, 1- octen-3-ol or mixture thereof, as a fumigant. In especially preferred uses of the present invention, the 1-octen-3-ol, 3-octanone, or mixture thereof is a molluscicide in a fumigant. Advantageously 1-octen-3-ol, 3-octanone, or mixtures thereof are particularly suited to use as molluscicides in fumigants due to their high volatility.

The present invention as hereinbefore described may be employed in any space requiring mollusc control. It may be used before or after the infestation of plants or plant propagation materials by mollusc. The invention may be used outdoors or indoors, in open or enclosed spaces. The present invention preferably provides the use as hereinbefore described in a field, glasshouse, cloche, polytunnel, shipping container, warehouse, garden, garden centre, barn or controlled environment room.

In the use of the present invention, the 3-octanone, 1-octen-3-ol or mixture thereof, may be applied to an area to be treated using any conventional application process. Preferably, 3-octanone, 1-octen-3-ol or mixture thereof is applied to an area to be treated by band application, basal application, broadcast application, crack and crevice application, directed-spray application, foliar application, soil application, soil incorporation, seed or tuber treatment coating, rope-wick treatment, wiper treatment, space treatment, spot treatment, drip irrigation, pelleting, dissolvable solid matrix, spraying and/or fumigation. Application by pelleting, spraying and/or fumigation is particularly preferred. Spraying may be carried out using a spray tank, spray plane, irrigation system or other conventional means.

In another particularly preferred use, the 1-octen-3-ol, 3-octanone, or mixture thereof is applied by fumigation. Thus a preferred use of the present invention is 1- octen-3-ol, 3-octanone, or a mixture thereof as a molluscicide in a fumigation process. Preferably fumigation is carried out in an enclosed space (e.g. in a glasshouse, cloche, polytunnel, shipping container, warehouse. The use in a fumigation process is especially preferred in the treatment of stored produce. In such a case the fumigation process may be carried out in a storage facility (e.g. in a glasshouse, cloche, polytunnel, shipping container, warehouse, barn or controlled environment room) before the produce is placed in the storage facility, after the produce is placed in the storage facility, or both before and after the produce is placed in the storage facility. The fumigation process may be employed once or may be repeated as required. In a preferred use, the 1-octen-3-ol, 3-octanone, or mixture thereof is applied by controlled release from a dispenser.

The present invention also provides a method of controlling molluscs, comprising applying an effective amount of 1-octen-3-ol, 3-octanone, or a mixture thereof, to an area requiring mollusc control. Advantages and preferred features of the method of the present invention are as hereinbefore described in relation to the use of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the avoidance behaviour of the garden snail to lettuce leaves inoculated with different amounts of conidia of Metarhizium brunneum strains V275 and ARESF4556;

Figure 2 shows slug, D. reticulatum, mortality (means with SE error bars) after contact with varying concentrations of 1-octene, 1-octen-3-ol, and 3-octanone over 24 hr;

Figure 3 shows snail, C. aspersum, mortality (means with SE error bars) after contact with varying concentrations of 1-octene, 1-octen-3-ol, and 3-octanone over 24 hr;

Figure 4 shows slug, D. reticulatum, mortality (means with SE error bars) after fumigation with varying concentrations of 1-octene, 1-octen-3-ol, and 3-octanone over 24 hr;

Figure 5 shows snail, C. aspersum, mortality (means with SE error bars) after fumigation with varying concentrations of 1-octene, 1-octen-3-ol, and 3-octanone over 24 hr;

Figure 6 shows the arena used to evaluate mollusc repellent properties of 1- octene, 1-octen-3-ol, and 3-octanone. The ventilated plastic container (30 x 13 x 13 cm) was partitioned in the middle by a piece of cardboard with a hole at the base to allow free movement of the animals between the two chambers of the test arena. Each chamber contained a Petri dish lined with filter paper with one being treated with different amounts of the active (5, 10, 25 & 50 pi) and the other treated with water only (control). Four animals (D. reticulatum or C. aspersum) were released from a Petri dish placed the middle of the chamber and their location recorded at 10 min, 0.5, 1 , 3 and 24 hr post-treatment;

Figure 7 shows slug repellence (means with SE error bars) over 24 hr, with varying concentrations of 1-octene, 1-octen-3-ol, and 3-octanone;

Figure 8 shows snail repellence (means with SE error bars) over 24 hr, with varying concentrations of 1-octene, 1-octen-3-ol, and 3-octanone;

Figure 9 shows slug mortality (means with SE error bars) with different volumes of aqueous formulations of 1-octen-3-ol, at varying concentrations, over 24 hr applied to the slug mantle; Figure 10 shows slug mortality (means with SE error bars) with different volumes of aqueous formulations of 3-octanone, at varying concentrations, over 24 hr applied to the slug mantle;

Figure 11 shows snail mortality (means with SE error bars) with different volumes of aqueous formulations of 1-octen-3-ol, applied by spraying to the snail mantle at varying concentrations, over 24 hr; and

Figure 12 shows snail mortality (means with SE error bars) with different volumes of aqueous formulations of 3-octanone, applied by spraying to the snail mantle at varying concentrations, over 24 hr.

EXAMPLES

Materials and Methods

• Collection and maintenance of molluscs.

The following slugs and snails were collected from local gardens and parks in Swansea: Garden snail ( Cornu aspersum), Great grey or leopard slug ( Umax maximus ), Black slug ( Arion ateή, Large red slug ( Arion rufus ), Grey field slug (Derocerus reticulatum) and Yellow slug ( Umax flavus). The specimens were collected at dawn or early evening and maintained in ventilated plastic containers at room temperature (21 ± 2 °C) until required. They were fed diverse plant materials (turf, flowers, lettuce leaves) and grouped according to body weight. Studies were conducted on immature D. reticulatum and C. aspersum which weighed 0.5-1 g and 1-3 g, respectively.

• Statistical Methods

For M. brunneum conidia avoidance studies, the mean and standard error were calculated. Survival was modelled using Generalised Linear Models (GLMs) with logit link functions and binomial error distributions. Since mortality after different time points was observed using different individuals, there was no issue of temporal correlation or censoring typically associated with longitudinal bioassays. Repellence was also modelled as binomial data (repelled vs. not repelled). Percentage weight changes were arcsine-transformed and modelled using Normal linear models. The effects of dose, time post treatment, and concentration where included, were modelled as categorical fixed effects and included as main effects and all interactions. In the case of binomial GLMs, over-dispersion was assessed (and found to be «2 in all cases) by comparing residual deviance to residual degrees of freedom. Statistical significance of explanatory variables was tested using likelihood ratio tests assuming a Chi-squared null distribution for binomial GLMs, and F-ratios for Normal models. All statistical analysis was performed using R v3.5.0 (R Core Team, 2018).

Example 1 - Collection of volatiles from M. brunnuem cultures

Metarhizium brunneum isolates V275 (Origin: Cydia pomonella, Austria) were maintained on Sabouraud Dextrose Agar, pH 5.6 (SDA) and the conidia from these cultures used in subsequent studies. VOCs were collected from M. brunneum cultures produced on several substrates including : (1) Osmotic Stress Medium (OSM, 8% glucose, 2% peptone, 5.5% agar, 5.5% KOI), (2) High C:N (75:1) medium (HCN, 9.1% glucose, 1 % peptone, 2% agar), (3) Intermediate C:N (35:1) medium ( ICN, 4% glucose, 1 % peptone, 2% agar), and (4) low C:N (10:1) medium (LCN, 0.6% glucose, 1 % peptone, 2% agar). VOCs were collected at two time points: 7 days and 14 days post-inoculation, which correspond with the mycelial and sporulating stages of the fungus. All media were obtained from Sigma Aldrich (Poole, UK) except peptone, which was obtained from Oxoid Ltd. Cultures were produced on 10 ml medium in 25 ml glass vials incubated in the dark at 25 °C. There were three replicates per treatment (isolate, culture medium) with the whole experiment being repeated twice.

Headspace VOCs were collected from the above treatments using a 50/30 mm Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/P DM S) solid phase microextraction (SPME) fibre (Supelco, Bellefonte, PA, USA) and analyzed using an Agilent 6890N Gas Chromatograph equipped with an HP-5MS fused capillary column (30 m x 0.25 mm x 0.25 pm film thickness), interfaced directly with an Agilent 5975 mass spectrometer. Helium was used as the carrier gas with a constant flow of 1.0 ml/min. Immediately after collection of VOCs, the SPME needle was inserted manually into the injection port (230 °C; splitless mode) of the GC-MS for thermal desorption and held for 2 minutes. After desorption, the oven was held at 40 °C for 2 min, then the temperature raised to 200 °C at a rate of 3 °C /min. Finally, the temperature was raised to 270°C at a rate of 8 °C /min and held at 270°C for 10 min. Mass spectra were scanned repeatedly over 35-650 amu. Ionization was performed in electron impact (El) mode at 70 eV. A blank run was performed after each analysis in order to confirm that no residual compound was polluting the fibre or column. Total ion current (TIC) chromatograms were integrated without any correction for co-elution and results were expressed as percent of the total peak area. All peaks were identified from their mass spectra by comparison with spectra in Wiley Registry (9^th edition) and NIST11 (National Institute of Standards and Technology, Gaithersburg, MD, USA) libraries. Identifications were confirmed by comparing the retention time (R_t), molecular ions, and fragmentation pattern with authentic standard samples. The peaks observed in the control (blank media without fungus) were excluded from the samples during the sample analysis. All reference compounds used for identification were purchased from Sigma Aldrich (Poole, UK).

The results are shown in Table 1 below.

Table 1 VOCs produced by M. brunneum V275 on different substrates. The values are percentage values and are proportional to the compound with the highest peak (100%) in the chromatogram. Values are means of 5 replicates. - indicates the VOC was not observed. Tr. indicates a trace amount of the VOC was observed. The results show that 1-octene-3-ol and 1-octene are both produced by the V275 strain of M. brunneum on different agar media.

The VOCs used in the examples below were purchased from Sigma Aldrich.

Example 2 - Snail avoidance of M. brunneum conidia To investigate whether molluscs avoided M. brunneum, the garden snail was provided with lettuce leaves (4 g wet weight) pre-coated with different doses (0.4, 0.2, 0.04g) of dry conidia of M. brunneum strains V275 and ARESF4556. The number of conidia per gram for strains V275 and ARSEF 4556 was 7.5 x 10¹⁰ and 4.4 x 10¹⁰ conidia, respectively. The control was leaves not treated with the fungus. Two snails, starved for 24 hrs, were placed in each assay pot 24 hrs after treating the leaves with the fungal inoculum. The assays were performed in a 300ml cylindrical plastic container at room temperature with leaf consumption based on residual weight being measured 24 and 48 hrs post treatment. There were five replicates per treatment and the whole study repeated twice.

Results

The results are shown in Figure 1.

Cornu aspersum fed less on lettuce leaves treated with conidia of M. brunneum V275 and ARSEF 4556 compared with the untreated control (Fig. 1). Feeding damage decreased with fungal dose and was more pronounced for strain V275 especially at the highest dose. The percentage lettuce leaf consumed was lower 24 hr than 48 hr post treatment for both strains (Fig. 1).

Example 3 - Contact toxicity study of D. reticulatum and C. aspersum with VOCs

Authenticated M. brunneum VOCs (1-octene, 1-oct-3-ol and 3-octanone) were evaluated against D. reticulatum and C. aspersum for contact toxicity.

Individual D. reticulatum and C. aspersum were placed in 9 cm diameter Petri dishes lined with Whatman filter paper moistened with water. The molluscs were exposed to 1 , 5 and 10 pi of each of 1-octene, 1-octen-3-ol and 3-octanone which was applied to the fleshy dorsal surface of the animal using an Accumax PRO Micropipette. Control animals were left untreated. The Petri dishes were sealed with Parafilm to prevent the animals escaping and loss of volatiles. Mortality was recorded 0.5, 1 , 3 and 24 hr post treatment. Slugs and snails were considered dead if they did not respond to probing with a needle (Abdelgaleil, 2010). There were 5 replicates per treatment with the whole experiment being repeated twice. Assays were conducted at room temperature (21 ± 2 °C).

To determine the mean time to death (MTD) the above experiments were repeated but mortality was recorded continuously. Results

Slugs exposed to the VOCs 1-octene, 1-octen-3-ol and 3-octanone vomited a brown liquid or exhibited contorted body movements, producing yellow or brown staining mucilage before shrinking and dying. Snails exposed to the VOCs withdrew into the shell or produced a yellow watery mucilage before dying often with their head exposed. Treating snails with aqueous diluted formulations triggered production of clear, frothy mucilage.

D. reticulatum and C. aspersum mortality was dependent upon the compound, dose and time post treatment (Table 2 and Figures 2 and 3). Figure 2 shows the contact effect on survival of the slug D. reticulatum. Figure 3 shows the contact effect on survival of the snail, C. aspersum. In both studies, 3-octanone and 1-octen-3-ol were significantly more potent than 1-octene.

Table 2: Percentage mortality and time to death of garden slug D. reticulatum (weight 0.5-2 g) and garden snail C. aspersum (weight 1-3 g) exposed to different volumes of

1-octene, 1-octen-3-ol and 3-octanone.

In the case of slugs D. reticulatum, 1-octene was unable to cause 100% mortality even at the highest concentration and longest times post-treatment. With the highest dose tested (10 mI) 60% mortality was achieved 24 hr post treatment. In contrast both 3-octanone and 1-octen-3-ol achieved much higher mortality results. At the medium (5 mI) and highest (10 mI) dose levels tested both of these compounds achieved 100 % mortality within 1 hr post-treatment. 3-octanone achieved 100% mortality within 0.5 h post treatment. These results can be seen in Figure 2.

In the case of the snail, C. aspersum, a similar pattern of results was observed. 1-octene did not cause mortality, other than with the highest dose (10 mI) for the longest post-treatment times. In contrast both 3-octanone and 1-octen-3-ol achieved mortality at 1 mI and 5 mI doses. At a dose of 10 mI, both 3-octanone and 1-octen-3-ol achieved 100 % mortality after 1 hr. These results can be seen in Figure 3.

Example 4 - Fumigation assay of D. reticulatum and C. aspersum using VOCs

Individual D. reticulatum and C. aspersum were exposed to different doses (1 , 5 and 10 mI) of 1-octene, 1-octen-3-ol and 3-octanone dispensed from a 5 mm diameter filter paper placed on a glass coverslip attached to the lid of a 9 cm diameter Petri dish. Control animals were left untreated. The Petri dishes were sealed with Parafilm to prevent the escape of animals and VOCs. Mortality was recorded 0.5, 1 , 3 and 24 hr post treatment. Slugs and snails were considered dead if they did not respond to probing with a needle (Abdelgaleil, 2010). There were 5 replicates per treatment with the whole experiment being repeated twice. Assays were conducted at laboratory temperature (21 ± 2 °C).

Results

As in the contact toxicity example above, 3-octanone and 1-octen-3-ol were found to be significantly more potent than 1-octene for both mollusc species.

In the fumigation assays of slugs, both 3-octanone and 1-octen-3-ol achieved 100 % mortality 1 hr post-treatment at doses of 10 mI. At lower doses 3-octanone and 1-octen-3-ol also achieved mortality. In contrast 1-octene only achieved 60 % mortality at a dose of 10 mI, 24 hr post treatment. These results can be seen in Figure 4.

In fumigation assays of snails, the results generally follow the same pattern. Thus both 3-octanone and 1-octen-3-ol achieved 100 % mortality 24 hr post treatment at a dose of 10 mI. In contrast 1-octene was barely active at all. These results can be seen in Figure 5. The difference in the level of activity achieved with the snails compared to the slugs is believed to be due to the ability of the snails to retreat into their shells.

Example 5 - Repellence Assay of VOCs Repellence by 1-octene, 1-octen-3-ol and 3-octanone was investigated using ventilated plastic containers (30 x 13 x 13 cm). Each container was partitioned in the middle by a piece of cardboard with a hole at the base to allow free movement of the animals between the two chambers of the test arena (Fig. 6). A 9 cm diameter Whatman filter paper was placed in each chamber with one paper being treated with different doses (5, 10, 25, 50 mI) of the active (1-octene, 3-octanone or 1-octen-3-ol) and the other with water (control). Four animals (D. reticulatum, C. aspersum) were released from a petri dish placed in the middle of the assay arena and number of animals in each chamber recorded at 10, 30, 60 and 180 min and then every 24 hr post-treatment.

The above study was repeated using C. aspersum only. In these assays, 4 g of fresh oilseed rape leaves were placed in each half of the test arena. Four snails starved for 24 hr were released in the middle and feeding damage assessed. Leaf damage, based on wet residual weight of the leaves, was determined 24 and 48 hr post treatment.

Both assays were conducted under the same laboratory conditions (21 ± 2 °C).

Results

Slugs were repelled by 1-octene but were repelled more by 3-octanone and 1- octen-3-ol. With 3-octanone and 1-octen-3-ol, completely repellence was observed for a number of the doses tested (see Figure 7)

Snails were repelled by 1-octene and 1-octen-3-ol to approximately the same extent. With 3-octanone, a higher degree of repellence, including complete repellence at the highest dose, was achieved (see Figure 8)

Example 6 - Evaluation of aqueous formulations of VOCs (direct application)

Individual D. reticulatum and C. aspersum were exposed to different volumes (10, 20, 50, 100 pi) of 3-octanone and 1-octen-3-ol diluted in water to 5%, 10% and 20% (v/v). Water was used as a control. The chemicals were applied using an Accumax PRO Micropipette to the fleshy dorsal surface of the animals. Individuals were placed in a 9 cm diameter Petri dish and sealed with Parafilm. Assays were conducted at room temperature (21 ± 2 °C) and the percentage mortality recorded 0.5, 1 , 3 and 24 hr post-treatment. There were 5 replicates per treatment.

Results Application of aqueous formulations of 3-octanone and 1-octen-3-ol to slugs showed that they both achieved slug mortality. With the active 1-octen-3-ol, mortality increased with dose (X2df = 3 = 80.1 , p < 0.001), time (X2df = 3 = 114, p < 0.001), and concentration (X2df = 3 = 207, p < 0.001) (Figure 9). Where 3-octanone was applied, mortality increased with dose (X2df = 3 = 143, p < 0.001), time (X2df = 3 = 51.5, p < 0.001), and concentration (X2df = 3 = 158, p < 0.001) (Figure 10).

Example 7 - Evaluation of aqueous formulations of VOCs (application by spraying)

Aqueous formulations were applied to plants infested with the molluscs using a 0.5 L hand-held sprayer (supplied by Screwfix). Briefly, 30 ml of 5% and 20% (v/v) aqueous 1 octen-3-ol and 3-octanone were sprayed onto 25 (30-day old) corn plants (Zea mais variety, Madlen, Maisadour Semences) grown in plastic trays (35 x 20 x 15 cm). Each tray was placed in a Bugdorm. Twenty D. reticulatum or C. aspersum were released onto the tray a few minutes before spraying. Mortality was recorded 3 and 24 hr post treatment.

Results

Application of aqueous formulations of 1-octen-3-ol and 3-octanone by spraying showed that they both achieved slug mortality. With 1-octen-3-ol mortality increased with dose (X2df = 3 = 35.6, p < 0.001), time (X2df = 3 = 24.8, p < 0.001), and concentration (X2df = 3 = 69.2, p < 0.001) (Figure 11). With 3-octanone mortality increased with dose (X2df = 3 = 12.1 , p = 0.007), time (X2df = 3 = 48.7, p < 0.001), and concentration (X2df = 3 = 138, p < 0.001) (Figure 12).

Conclusion

These experiments show that the fungal VOCs 1-octen-3-ol and 3-octenone are toxic to the terrestrial molluscs D. reticulatum and C. aspersum on contact or when deployed as fumigants. 1-octen-3-ol and 3-octenone are significantly both more potent that 1-octene. Both D. reticulatum and C. aspersum try to avoid direct exposure or food tainted by 1-octen-3-ol and 3-octenone. Both molluscs produced secretions in response to 1-octen-3-ol and 3-octenone.

Application of aqueous formulations of 1-octen-3-ol and 3-octanone showed that mortality was dose-related and that slugs were more susceptible to these compounds than snails. The fact that significant mortality was observed 24 hr post- treatment suggests that either 1-octen-3-ol and 3-octanone continue to cause damage or substantial irreparable damage from which the animal could not recover.

The results show that 1-octen-3-ol and 3-octanone are molluscicides. Their use as molluscicides has many ecological benefits. For example, they are natural and ephemeral so leave no residues. They also do not pose a threat to non-target animals including predators and decomposers.

Claims

CLAIMS:

1. Use of 3-octanone, 1-octen-3-ol or a mixture thereof as a molluscicide.

2. The use as claimed in claim 1 , wherein 3-octanone is the molluscicide.

3. The use as claimed in claim 1 , wherein 1-octen-3-ol is the molluscicide.

4. The use as claimed in any preceding claim, wherein said 3-octanone, 1-octen-

3-ol or mixture thereof is used in the form of a composition, wherein said composition comprises one or more additional ingredients.

5. The use as claimed in claim 4, wherein said composition is a solid composition.

6. The use as claimed in claim 5, wherein said solid composition is in the form of granules.

7. The use as claimed in claim 5, wherein said composition is a liquid composition.

8. The use as claimed in claim 5, wherein said composition is a slurry composition.

9. The use as claimed in any one of claims 4 to 9, wherein said one or more additional ingredients comprise active ingredients, preferably further molluscicides.

10. The use as claimed in any preceding claim to control gastropods.

11. The use as claimed in claim 10, wherein said gastropod is a slug.

12. The use as claimed in claim 10, wherein said gastropod is a snail.

13. The use as claimed in any one of claims 1 to 12 as a fumigant.

14. The use as claimed in any one of claims 1 to 13 to treat agricultural crops.

15. The use as claimed in any one of claims 1 to 13 to treat horticultural crops.

16. The use as claimed in any one of claims 1 to 13 during storage.

17. The use as claimed in any preceding claim in a field, glasshouse, cloche, polytunnel, garden or garden centre.

18. A method of controlling molluscs, comprising applying an effective amount of 3- octanone, 1-octen-3-ol or mixture thereof, to an area requiring mollusc control.