Biocide activator.

0001This invention relates to an agricultural and horticultural biocide activator. More particularly, it relates to an agricultural and horticulural biocide activator in which the dose of an agricultural chemical can be reduced and the expression of resistance to the biocide by disease causing agents and insect pests can be suppressed.

0002Common agricultural and horticultural biocides include bactericides, insecticides, acaricides and herbicides. However, those which inhibit specific enzymatic/metabolic systems frequently suffer from disadvantages in that they become increasingly ineffective against disease causing microorganisms and insect pests which have acquired a resistance against the same. As a result, it is necessary to use larger amounts of the biocide until its application becomes impractical.

0003A biocide having a low basic activity will need to be applied in a large amount in order to completely control diseases and insect pests. However the application of a large amount of an agricultural chemical not only causes environmental pollution but also restricts the range of available agricultural chemicals. There is therefore, a need for a highly safe chemical which can suppress the expression of resistance to a biocide in disease causing agents and insect pests and enhance the effect thereof.

0004The present inventors have found that a compound obtained by substituting a counter ion of a quaternary ammonium salt with an anion residue of an acid of an anionic oligomer or polymer having a molecular weight of from 300 to 20,000 can enhance the effect of a biocide and unexpectedly improve its effect on disease causing agents and insect pests having a resistance to various biocides without any adverse effects on plants.

0005Accordingly, the present invention provides a biocide activator which comprises a compound represented by the following general formula (I) as an essential ingredient: <chemistry id="chem0001" num="0001"><img file="EP0453086A2_D0001.tif" /></chemistry>    wherein at least one of R¹, R² and R³ represents a straight-chain or branched alkyl or alkenyl group having 8 to 30 carbon atoms while other(s) represent a group or a combination selected from -CH₃, -CH₂CH₃, <chemistry id="chem0002" num="0002"><img file="EP0453086A2_D0002.tif" /></chemistry> and <chemistry id="chem0003" num="0003"><img file="EP0453086A2_D0003.tif" /></chemistry> groups (wherein n ranges from 1 to 5; R⁴ represents a -CH₃ or -CH₂CH₃ group; and a counter ion X^⊖ is an anion residue of an acid of an anionic oligomer or polymer having an average molecular weight of from 300 to 20,000.

0006The biocidal effect of a biocide can be enhanced with the use of an effective amount of a biocide activator having the formula (I).

0007Preferably the invention provides a biocide composition which comprises a biocide and the biocide activator and more preferably an aqueous biocide solution or suspension which comprises an biocidally effective amount of a biocide and the biocide activator. The invention additionally provides a biocide activator as defined herein.

0008It is preferable that the solution or suspension comprises 0.01 to 60 percent by weight of the biocide activator.

0009It is preferable that the anionic oligomer or polymer is selected from the below shown groups (1) to (3).

0010The anionic oligomer or polymer to be used in the present invention may preferably comprises one or more compounds selected from compounds 1) to 3): <ul id="ul0001" list-style="none"><li>1) a polymer comprising one or more monomers selected from unsaturated carboxylic acids and derivatives thereof as an essential component;</li><li>2) a polymer comprising styrenesulfonic acid as an essential constituting monomer; and</li><li>3) a formalin condensate of a sulfonate of a polycyclic aromatic compound optionally having a hydrocarbon group as a substituent.</li></ul>

0011The quaternary ammonium salt represented by the general formula (I) relating to the present invention is characterized by its counter ion. It is important that the counter ion X^⊖ is an anion residue of an acid of an anionic oligomer or polymer having a molecular weight of from 300 to 20,000 and that said anionic oligomer or polymer has an anion residue of an acid which may fundamentally give the counter ion X^⊖. The anionic oligomers or polymers to be used in the present invention, as specified in the above items 1) to 3), will now be described in detail. <ul id="ul0002" list-style="none"><li>1) A polymer comprising one or more monomers selected from among unsaturated carboxylic acids and derivatives thereof as an essential component. Preferred examples of the monomer to be used in the preparation of the polymer 1) include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acid such as maleic acid and derivatives thereof such as alkyl esters of the above-mentioned acid (for example, methyl esters) and polyoxyethylene esters. In addition to these monomers, copolymerizable monomers such as vinyl acetate, isobutylene, diisobutylene and styrene may be used. These monomers may be polymerized by conventional methods. Neither the ratio of the monomers nor the degree of polymerization is particularly restricted. Preferred examples thereof include polyacrylic acid, polymethacrylic acid, acrylic acid/methacrylic acid copolymer, acrylic acid/polyoxyethylene methacrylate copolymer, acrylic acid/methyl acrylate copolymer, acrylic acid/vinyl acetate copolymer, acrylic acid/maleic acid copolymer, maleic acid/isobutylene copolymer and maleic acid/styrene copolymer. Two or more polymers selected from the above compounds may be employed. Furthermore, they may be converted into salts of alkali metals, ammonia or organic amines in such a manner so as not to deteriorate the performance thereof.</li><li>2) A polymer comprising styrenesulfonic acid as an essential constituting monomer. The homopolymer of styrenesulfonic acid may be prepared by polymerising styrenesulfonic acid or by sulfonating polystyrene. Styrenesulfonic acid polymer has a skeleton represented by the following formula: <chemistry id="chem0004" num="0004"><img file="EP0453086A2_D0004.tif" /></chemistry> The molecular weight thereof may range from 300 to 20,000, and preferably from 300 to 10,000. Alternatively, a copolymer of styrenesulfonic acid with other monomer(s) may be prepared by copolymerizing styrenesulfonic acid with the monomer(s) or by sulfonating a copolymer of styrene with other monomer(s). Examples of the preferred monomers for copolymerization include hydrophobic monomers such as alkyl acrylates, alkyl methacrylates, vinyl alkyl ethers, vinyl acetate, ethylene, propylene, butylene, butadiene, diisobutylene, vinyl chloride, vinylidene chloride, acrylonitrile and styrene and hydrophilic ones such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, vinyl alcohol, acrylamide, methacrylamide, diacetone acrylamide, N-vinylpyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, methacrylsulfonic acid, xylenesulfonic acid and naphthalenesulfonic acid. Preferred examples of the copolymer include (meth)acrylic acid/styrenesulfonic acid copolymer. The molar ratio of the (meth)acrylic acid to the styrenesulfonic acid in the copolymer may range from 1/10 to 10/1, and preferably from 1/3 to 4/1. The average molecular weight of the copolymer may range from 300 to 20,000, and preferably from 1,000 to 10,000. The copolymer may further contain a neutralized portion of a salt such as sodium salt, potassium salt, ammonium salt, diethanolamine salt, triethanolamine salt, monoisopropanolamine salt, diisopropanolamine salt, triisopropanolamine salt or 2-amino-2-methylpropane-1,3-diol salt, so long as the performance of the copolymer is not deteriorated thereby.</li><li>3) A formalin condensate of a sulfonate of a polycyclic aromatic compound optionally having a hydrocarbon group as a substituent. Preferred examples thereof include formalin condensates of petroleum sulfonic acid derivatives, ligninsulfonic acid derivatives, naphthalenesulfonic acid derivatives, xylenesulfonic acid derivatives and alkylbenzenesulfonic acid derivatives.</li></ul>

0012The above-mentioned compound 3) may be obtained by, for example, sulfonating a compound such as naphthalene, an alkyl-substituted benzene, an alkyl-substituted naphthalene, anthracene, an alkyl-substituted anthracene, lignin or a compound contained in a petroleum residue having an aromatic ring by a conventional method and then condensing the obtained sulfonate with formalin. In this case, the degree of condensation is preferably 2 or above, and more preferably from 3 to 30. When the molecular weight of the obtained condensate is smaller than 300, the condensation can give only a limited effect, causing some problems in practice.

0013Preferred examples of the aromatic compound to be used in the above process include lignin, xylene, toluene, naphthalene and alkyl-naphthalenes having an alkyl group of 1 to 6 carbon atoms. Mixtures thereof may also be employed.

0014Furthermore, a salt of an alkali metal such as sodium or potassium, an alkaline earth metal such as calcium, an amine or ammonium may be used, so long as that does not adversely affect the performance of the obtained compound.

0015The quaternary ammonium salt represented by the general formula 1) may be prepared by, for example, converting a quaternary ammonium salt having a halogen atom as a counter ion into a quaternary ammonium of OH-type by using an ion exchange resin and then neutralizing the obtained product with an oligomer or a polymer having an anion residue of the acid as described above. It may additionally include an alkali metal salt, an amine salt or an organic amine salt, so long as its performance is not adversely affected.

0016The biocide activator of the present invention may be mixed and diluted with a biocide and then applied to plants or soil. In the application thereof, it is preferable to use the above-mentioned quaternary ammonium salt, as an essential ingredient, at a concentration of from 0.01 to 60% by weight.

0017The compound of the present invention may be applied as an aqueous solution, wettable powder, granules, dust, emulsion, or an oil or paste. Therefore other additives, for example, salts, surfactants, thickeners and carriers may be added depending on the selected formulation.

0018Examples of preferred salt additives include metal salts of carboxylic acids, such as succinates, malonates, citrates, gluconates and glutarates, metal salts of phosphoric acid compounds such as tripolyphosphates and hexametaphosphates and inorganic salts such as Na₂SO₄ and MgSO₄. Either one of these salts or a mixture thereof may be employed.

0019As the surfactants, nonionic and anionic surfactants may be used. Preferred examples of the nonionic and/or anionic surfactants include nonionic surfactants such as polyoxyethylene (hereinafter simply referred to as POE) alkyl (carbon atom number: 6 - 22) ethers, POE alkyl (carbon atom number: 4 - 18) phenol ethers, polyoxypropylene polyoxyethylene (block or random) alkyl ethers, POE phenylphenol ether, POE styrenated phenol ether and POE tribenzylphenol ether; and anionic surfactants such as ligninsulfonate salts, alkylbenzenesulfonate salts, alkylsulfonates salts, POE alkylsulfonate salts, POE alkylphenyl ether sulfonate salts, POE alkylphenyl ether phosphate salts, POE phenylphenol ether sulfonate salts, POE phenylphenol ether phosphate salts, naphthalenesulfonate salts, naphthalenesulfonic acid/formalin condensate, POE tribenzylphenol ether sulfonate salts and POE tribenzylphenylphenol ether phosphate salts. These surfactants can be used singly or as a mixture.

0020The content of each of these surfactants in the biocide may range from 0 to 20% by weight, and preferably from 1 to 10% by weight.

0021Natural semisynthetic or synthetic water-soluble thickeners may be used. Preferred examples of the natural thickeners include xanthan gum and Zanflo originating from microorganisms and pectin, gum arabic and guar gum originating from plants. Preferred examples of the semisynthetic thickeners include methylated products, carboxyalkyated products and hydroxyalkylated products of cellulose or starch derivatives (including methylcellulose, carboxymethyl-cellulose and hydroxymethylcellulose) and sorbitol. Preferred examples of the synthetic thickeners include polyacrylate salts, polymaleate salts, polyvinylpyrrolidone and EO adduct of pentaerythritol.

0022The above water-soluble thickeners may be used in the biocide in an amount of from approximately 0 to 3.0% by weight, and preferably from 0.05 to 0.5% weight.

0023As the carrier, inorganic mineral salts and water-insoluble polymers may be employed. Preferred examples of the inorganic mineral salts include inorganic salt clay, talc, bentonite, calcium carbonate, diatomaceous earth and white carbon. Preferred examples of the water-insoluble polymers include styrenesulfonic acid, 2-acrylamide, 2-methylpropanesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid and polymers of salts thereof. Further, copolymers obtained by copolymerizing the above-mentioned copolymer with a hydrophobic monomer such as an alkyl acrylate, an alkyl methacrylate, vinyl alkyl ethers, vinyl acetate, ethylene, propylene, butylene, butadiene, diisobutylene, vinyl chloride, vinylidene chloride, acrylonitrile or styrene; or a hydrophilic monomer such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, vinyl alcohol, acrylamide, methacrylamide, diacetone acrylamide or N-vinylpyrrolidone may be employed.

0024The biocide activator of the present invention exhibits no adverse effect on various crops and thus can be applied safely.

0025Examples of preferred biocides for activation by the biocide activator of the present invention are as follows.

0026Examples of bactericides include Dithane (zinc ethylenebisdithiocarbamate), Maneb (manganese ethylenebisdithiocarbamate), Thiuram [bis(dimethylthiocarbamoyl) disulfide], Manzeb (zinc/manganese ethylenebisdithiocarbamate), Bisdaithane (bisdimethyldithiocarbamoylzinc ethylenebisdithiocarbamate), Propineb (zinc propylenebisdithiocarbamate), benzimidazole derivatives such as Benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate) and Thiophanate-methyl[1,2-bis(3-methoxycarbonyl-2-thioureido)benzene], as well as Vinclozolin [3-(3,5-dichloropheyl)-5-methyl-5-vinyl-1,3-oxazolidine-2,4-dione], Iprodione [3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxoimidazolidine-1-carboxamide], procymidone® [N-(3,5-dichlorophenyl)-1_,2-dimethylcyclopropane-1,2-dicarboximide], Triazine [2,4-dichloro-6-(2-chloroanilino)-1,3,5-triazine], triflumizole® [(E)-4-chloro-α,α,α-trifluoro-N-(1-imidazol-1-yl-2-propoxyethylidane)-o-toluidine], Metalaxyl [methyl N-(2-methoxyacetyl)-N-(2,6-xylyl)-D,L-araninate], bitertanol® [all-rac-1-(biphenyl-4-yloxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)2-butan-2-ol], triadimefon® [1-(4-chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)-2-butanonel, Isoprothiolane (diisopropyl 1,3-dithiolan-2-ylidenemalonate), Daconil (tetrachloroisophthalonitrile), Pansoil® (5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole), Rabcide (4,5,6,7-tetrachlorophthalolide), Kitazin P (0,0-diisopropyl-S-benzyl thiophosphate), Hinosan (0-ethyl-S,S-diphenyl thiophosphate), probenzol® (3-allyloxy-1,2-benzisothiazole 1,1-dioxide) and Captan (N-trichloromethylthiotetrahydrophthalimide).

0027Examples of insecticides include pyrethroid insecticides such as Fenvalerate [α-cyano-3-phenoxybenzyl 2-(4-chlorophenyl)-3-methylbutanoate) and Baytroid [cyano-4-fluoro-3-phenoxyphenylmethyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate); organophosphorus insecticides such as DDVP (dimethyl 2,2-dichlorovinyl phosphate), Sumithion [0,0-dimethyl-0-(3-methyl-4-nitrophenyl) thiophosphate], Malathon (S-[1,2-bis(ethoxycarbonyl)ethyl] dimethyl phosphorothionate), Dimethoate [dimethyl S-(N-methylcarbamoylmethyl) dithiophosphate], Elsan (S-[α-ethoxycarbonyl)benzyl] dimethyl phosphorothiolthionate) and Baycid [0,0-dimethyl 0-(3-methyl-4-methylthiophenyl) thiophosphate]; carbamate insecticides such as Bassa (0-butylphenyl methylcarbamate), MTMC (m-tolyl methylcarbamate), Meobal (3,4-dimethylphenyl N-methylcarbamate) and NAC (1-naphthyl N-methylcarbamate); as well as Methomyl (S-methyl-N-[(methylcarbamoyl)oxylthioacetimide) and Cartap [1,3-bis(carbamoylthio)-2-(N,N-dimethylamino)propane hydrochloride.

0028Examples of acaricides include Smite® (2-[2-p-tert-butylphenoxy)isopropoxy]isopropyl 2-chloroethyl sulfide), Acricid (2,4-dinitro-6-sec-butylphenyl dimethylacrylate), Chlormite® (isopropyl 4,4-dichlorobenzilate), Akar (ethyl 4,4-dichlorobenzilate), Kelthane [1,1-bis(p-chlorophenyl)-2,2,2-trichloroethanol), Citrazon (ethyl 0-benzoyl-3-chloro-2,6-dimethoxybenzohydroxymate), Omite [2-(p-tert-butylphenoxy)cyclohexyl 2-propynyl sulfite], Osadan [hexakis(β,β-dimethylphenylethyl)distannoxane], hexithiazox® [trans-5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-oxothiazolidine-3-carboxamide] and Amitraz [3-methyl-1,5-bis(2,4-xylyl)-1,3,5-triazapenta-1,4-diene].

0029Examples of herbicides include Stam (3,4-dichloropropionanilide), Saturn [S-(4-chlorobenzyl) N,N-diethylthiolcarbamate], Glyphosate [N-(phosphonomethyl)glycine isopropylamine salt], DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylureal and Glamoxone (1,1-dimethyl-4,4'-dipyridium dichloride).

0030Furthermore, plant growth regulators such as MH (maleic acid hydrazide and Ethrel (2-chloroethylphosphonic acid) may be cited.

0031The biocide composition of the present invention may further contain one or more plant growth regulators, fertilizers and/or preservatives.

0032The biocide activator of the present invention may be added to each of the aforesaid compositions and formulated. Alternatively, it may be diluted in use. The effect of suppressing resistance to biocides, according to the present invention, may be achieved by employing each of these methods.

0033Although a precise mechanism for the effect of the biocide activator of the present invention, namely enhancing biocidal effects and suppressing biocide-resistance, is not yet clear, it is thought that the biocide activator of the present invention may be adsorbed by the cell membrane of a bacterium, thereby disturbing its permeability. Alternatively it may inhibit the activity of membrane-bound enzymes which are localized on the surface of the bacterium, thereby damaging the bacterium and reducing its resistance to biocides. A similar effect was also found to be produced in relation to insecticides and acaricides.

0034The present invention will now be described by way of example only, with reference to the following Examples.

0035Table 1 shows the quaternary ammonium salts of the compound of the present invention and Formulation Examples will be given thereafter. <tables id="tabl0001" num="0001"><img file="EP0453086A2_D0005.tif" /></tables><tables id="tabl0002" num="0002"><img file="EP0453086A2_D0006.tif" /></tables><tables id="tabl0003" num="0003"><img file="EP0453086A2_D0007.tif" /></tables><tables id="tabl0004" num="0004"><img file="EP0453086A2_D0008.tif" /></tables><tables id="tabl0005" num="0005"><img file="EP0453086A2_D0009.tif" /></tables>

Example 1

003610 ml/pot of a spore suspension (10⁷/ml) of <u style="single">Botrytis cinerea,</u> exhibiting resistence to bactericides, was applied to young cucumber seedlings at the trifoliate stage. Next, the seedlings were allowed to stand at 25°C under a relative humidity of 90% for one day. In Test Examples 1 to 5, the biocide activators obtained in the above Formulation Examples 1 to 5 were added to a solution of marketed Benomyl (active ingredient concentration: 250 ppm) in such a manner as to dilute each of the activator 1000-fold. In Test Example 6 and Comparative Test Examples 1 and 2, on the other hand, the dilution was effected in such a manner as to give the content of the active ingredient of Benomyl of 250 ppm. Then each of the obtained samples was applied in a dose of 5 ml per pot. In Comparative Test Example 3, the procedure of Test Example 1 was repeated except that no Benomyl was added.

0037Next, the seedlings were allowed to stand at 25°C under a relative humidity of 85%. After 4 days, the lesions which had formed on each seedling were counted and the preventive value based on the control group was calculated in accordance with the following equation:<maths id="math0001" num=""><img file="EP0453086A2_D0010.tif" /></maths> Table 2 shows the results. <tables id="tabl0006" num="0006"><img file="EP0453086A2_D0011.tif" /></tables>

Example 2

0038The efficiency of an insecticide (Supracid) was examined by the Chinese cabbage leaf dipping method with the use of <u style="single">Myzus persicae</u> Sulzer imagines (each lot having 30 imagines) by three times.

0039The preventive value was determined based on the data of a control group.

0040In Test Examples 1 to 5, the biocide activators obtained in Formulation Examples 1 to 5 were mixed with a 180 ppm solution of marketed Supracid in such a manner as to dilute each of the activators 1000-fold. In Test Example 6 and Comparative Test Examples 1 and 2, on the other hand, the dilution was effected in such a manner as to give a content of the Supracid active ingredient of 180 ppm. In Comparative Test Example 3, the procedure of Test Example 2 was repeated except no Supracid was added.

0041Table 3 shows the results. <tables id="tabl0007" num="0007"><img file="EP0453086A2_D0012.tif" /></tables>

Example 3

0042Acaricidal effects were examined in a field, wherein <u style="single">Panonychus citri</u> McGregor resistant to marketed acaricide (Osadan) bred, by using three Citrus unshu trees per group.

0043In Test Examples 1 to 5, the biocide activators obtained in Formulation Examples 1 to 5 were mixed with a 125 ppm solution of the marketed Osadan in such a manner as to dilute each of the activators 1000-fold. In Test Example 6 and Comparative Test Examples 1 and 2, on the other hand, the dilution was effected in such a manner as to give a content of the Osadan active ingredient of 125 ppm. In Comparative Test Example 3, the procedure of Test Example 1 was repeated except no Osadan was added.

0044Then 3, 10, 20 and 30 days after the treatment with the chemicals, mites on 30 leaves per tree were counted and the preventive value of each group was calculated based on the data obtained in the control lot.

0045Table 4 shows the results. <tables id="tabl0008" num="0008"><img file="EP0453086A2_D0013.tif" /></tables>

Example 4

0046The effect of the biocide activator of the present invention on plants was examined in the following manner. Namely, cucumber, kidney bean, tomato, eggplant and strawberry plants were grown in a green-house and the effect of the compound on fruits and leaves of these crops was examined.

0047Table 5 shows the results. <tables id="tabl0009" num="0009"><img file="EP0453086A2_D0014.tif" /></tables>

Results

0048As the Examples 1 to 4 show, the biocide activator of the present invention apparently enhances biocidal effects without any adverse effects on crops.