Activator for Biocide

The present invention relates to an activator for biocides.

Biocides such as insecticides, germicides, herbicides and plant growth regulators have been used in the form of an emulsion, wettable powder, flowable product, grains or powder.

The physical properties of the biocides have been modified variously so as to exhibit the activity of the active ingredient sufficiently. However, it has been impossible to further increase the effects of the biocide.

It is quite significant to further increase the effects of known biocides, since the development of new biocides is now very difficult.

After intensive investigations, the inventors have found that specified compounds are effective in further activating various biocides. The present invention has been completed on the basis of this finding.

The invention provides a biocide composition which comprises an effective amount of a biocide and an effective amount of a biocide activator selected from the group consisting of an alkyl phosphate, an alkenyl phosphate, a hydroxyalkyl phosphate, a polyoxyalkylene alkyl ether phosphate, a salt thereof, a polyoxyalkylene alkenyl ether phosphate, a salt thereof, a polyoxyalkylene hydroxyalkyl ether phosphate and a salt thereof. The invention may be provided in the form of an emulsion concentrate which comprises 10 to 70 weight percent of the biocide and 10 to 50 weight percent of the biocide activator, 3 to 20 weight percent of an emulsifier and 10 to 50 percent weight of an organic solvent, or a dilute composition which comprises 100 to 5,000 ppm of the biocide, 200 to 10,000 ppm, preferably 500 to 5,000 ppm, of the biocide activator and a carrier for dilution. The diluent composition is usually prepared just in advance to use thereof.

The alkyl phosphates, polyoxyalkylene alkyl ether phosphates and salts of them according to the present invention may be prepared by known processes. For example, they are obtained by reacting an alcohol (if necessary, after addition of an alkylene oxide thereto) with phosphorus pentoxide and, if necessary, neutralizing the reaction product.

The starting alcohol has 1 to 22 carbon atoms and contains a straight-chain or branched alkyl group, an alkenyl group having double bond(s) or hydroxyl group(s) in the chain or a hydroxyalkyl group. The alcohol contains preferably 4 to 18 carbon atoms, 0 to 4, preferably 0 to 2 double bonds and 0 to 4, preferably 0 to 2, hydroxyl groups. The alcohols include, for example, butanol, 2-ethylhexanol, lauryl alcohol, stearyl alcohol and oleyl alcohol.

The alkylene oxides to be added to the alcohol to form a polyoxyalkylene chain include ethylene oxide, propylene oxide and butylene oxide. They may be used either alone or in the form of block or random adducts of two or more of them. The mol number of addition is 1 to 100, preferably 1 to 50.

The addition reaction may be carried out by a known process by, for example, introducing an alkylene oxide into an alcohol in the presence of an acid or alkaline catalyst at 50.degree. to 200.degree. C. under 1 to 5 kg/cm.sup.2. The alcohol or polyoxyalkylene alkyl ether may be phosphated by various processes. For example, 3 mol of the alcohol or polyoxyalkylene alkyl ether is reacted with 1 mol of phosphorus pentoxide at 80.degree. to 100.degree. C. for about 6 h to obtain a corresponding phosphate easily. The obtained alkyl phosphate or polyoxyalkylene alkyl ether phosphate is a mixture of a monoester and a diester in substantially equal amounts. Though excellent effects are exhibited when the activator for biocides of the present invention is any of the monoester and the diester, particularly excellent effects are obtained when it is a monoester, particularly a polyoxyalkylene alkyl ether/phosporic monoester or a salt thereof.

When said phosphate is neutralized with a base, a corresponding polyoxyalkylene alkyl ether phosphate salt is obtained. This ester salt also has an excellent activating effect. The salts include alkali metal, alkaline earth metal, monoethanolamine, diethanolamine, triethanolamine and ammonium salts.

When the activator for biocides of the present invention is used in combination with a biocide, the effect of the biocides can be increased 2 or 3-folds irrespective of the variety of the biocide.

The activator of the present invention is used in an amount of 0.05 to 20, preferably 1 to 15 parts by weight per part by weight of the biocide.

The biocide may be in the form of any of an emulsion, flowable product, wettable powder and powder. Therefore, other additives such as an emulsifying agent, dispersant and carrier may be incorporated therein according to the form of the biocide.

The activator of the present invention may be used by incorporating the same into the biocide of the above-mentioned form according to the formulation or by applying the same to a subject in combination with the biocide at the time of the application of the biocide in a diluted form. The activating effect according to the invention can be obtained in both cases.

Though the mechanism of such a remarkable activation of the biocide by the activator of the present invention has not been fully elucidated yet, it may be presumed that the activator for biocide of the present invention has an extremely high power of solubilizing the biocide irrespective of the structure of the biocide and, therefore, the biocide is finely divided and the penetration thereof through the surfaces of plants or into insects and germs is accelerated.

The present invention provides also a biocidal process characterized by spraying an emulsion (or dispersion) of a biocide containing the above-described activator.

Examples of the biocides which are activated by the activator of the present invention will be given below, which by no means limit the biocides to be activated according to the present invention. The activator of the present invention can be used safely without damaging the farm products. The insecticides include pyrethroid insecticides such as Fenvalerate [.alpha.-cyano-3-phenoxybenzyl-2-(4-chlorophenyl)-3-methylvalerate] and Pyrethroid [cyano(4-fluoro-3-phenoxyphenylmethyl-3-(2,2-dichloroethenyl)-2,2-dimethyl cyclopropanecarboxylate]; organophosphorus insecticides such as DDVP (2,2-dichlorovinyldimethyl phosphate), Sumithion (dimethyl-4-nitro-m-tolylphosphorothionate), Malathon {S-[1,2-bis(ethoxycarbonyl)ethyl]dimethylphosphorothiol thionate}, Dimethoate [dimethyl-S-(N-methylcarbamoylmethyl)phosphorothiol thionate), Elsan {S-[.alpha.-(ethoxycarbonyl)benzyl]dimethylphosphorothiol thionate) and Baycid [O,O-dimethyl-O-(3-methyl-4-methylmercaptophenyl)thiophosphate]; carbamate insecticides such as Bassa (O-butylphenyl methylcarbamate), MTMC (m-tolyl methylcarbamate), Meobal (3,4-dimethylphenyl-N-methylcarbamate), NAC (1-naphthyl-N-methylcarbamate); as well as Methomyl {methyl-N[(methylcarbamoyl)oxy]thioacetimide} and Cartap {1,3-bis(carbamoylthio)-2-(N,N-dimethylamino)propane hydrochloride].

Examples of acaricides include Smite {2-[2-(p-tert-butylphenoxy)isopropoxy]isopropyl-2-chloroethyl sulfide}, Acricid (2,4-dinitro-6-sec-butylphenyl dimethylacrylate), Chlormit (isopropyl 4,4-dichlorobenzylate), Acar (ethyl 4,4-dichlorobenzylate), Kelthane [1,1-bis(p-chlorophenyl)-2,2,2-trichloroethanol], Citrazon (ethyl O-benzoyl-3-chloro-2,6-dimethoxybenzohydroxymate), Plictran (tricyclohexyltin hydroxide) and Omite [2-(p-tert-butylphenoxy)cyclohexyl-2-propinyl sulfite].

Examples of the germicides include organosulfur germicides such as Dithane (zinc ethylenebisdithiocarbamate), maneb (manganese ethylenebisdithiocarbamate), thiuram [bis(dimethylthiocarbamoyl) disulfide], Benlate [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], Difolatan (N-tetrachloroethylthio-4-cyclohexane-1,2-dicarboxyimide), Daconol (tetrachloroisophthalonitrile), Pansoil (5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole), Thiophanate-methyl[1,2-bis(3-methoxycarbonyl-2-thioureido)benzene], Rabcide (4,5,6,7-tetrachlorophthaloid), Kitazin P (O,O-diisopropyl-S-benzyl phosphorothioate), Hinosan (O-ethyl-S,S-diphenyldithiophosphate) and Propenazol (3-allyloxy-1,2-benzothiazole 1,1-dioxide).

Examples of the herbicides include Stam (3,4-dichloropropionanilide), Saturn [S-(4-chlorobenzyl) N,N-diethylthiolcarbamate), Lasso (2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide), Glyphosate [N-(phosphonomethyl)glycine isopropylamine salt], DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea) and Gramoxone (1,1'-dimethyl-4,4'-dipyridium dichloride].

Examples of the plant growth regulating agents include MH (maleic acid hydrazide) and Ethrel (2-chloroethylphosphonic acid).

The following examples will further illustrate the activators for biocides of the present invention.

A compound of the present invention was dissolved in a commercially available herbicide (Karmex wettable powder, Simazine wettable powder, Paraquat solution or Glyphosate solution) to obtain a 0.2% solution. 10 ml of the solution was sprayed to each pot of crabgrass (a weed of Gramineae) which had been grown uniformly. The herbicidal effects of them were compared with one another. The crabgrasses used were in a three- or four-foliate period having a height of about 10 cm. Each pot had 25 crabgrasses. The dilution rate of said Karmex wettable powder, Simazine wettable powder, Paraquat solution or Glyphosate solution was 1/300. The herbicidal rate was determined by weighing the above-the-ground parts of the crabgrasses 10 days after the spraying and the results were represented by percentage based on the weight of untreated grasses. The results are shown in Table 1.

Third-instar larvae of plant hoppers were cultured and the insecticidal effects of insecticides thereon were examined by the leaf dipping method 3 repetition. Each group consisted of 10 larvae. The insecticidal effects were compared with those in an untreated group 24 h after the treatment. The results are shown in Table 2.

The insecticides used were a Sumithion emulsion and a Malathon emulsion each diluted to a concentration of 1/2000. The concentration of the activator of the present invention was controlled to 0.1% based on the diluted emulsion.

Male imagines of two-spotted red spider were applied to leaf disks of kidney beans in three replications. Each group consisted of 30 imagines. After the culture at 25.degree. C. for 24 h. 0.2 ml per each group of a test sample was sprayed by the chromatospray method. The insecticidal rate was determined by comparison with the results of an untreated group 24 h after the treatment. The acaricides used were Amitraz emulsion and Osadan wettable powder diluted to a concentration of 1/2000. The concentration of the activator of the present invention was controlled to 0.1% based on the diluted product. The results are shown in Table 3.

It is apparent from Examples 1 to 3 that the activators of the present invention have an excellent activating effect. In addition, each composition as prepared in Examples 1 to 3 was diluted with water. The obtained dilute one was effective to improve the biocide activity. Each component content in the dilute compositions is given below.