MITICIDE

Abstract: Quaternary ammonium salts represented by general formula (I), (wherein R₁ and R₂ each represents (II), (III) or C₁₋₄ alkyl with at least one being (II), R₅ represents C₄₋₂₂ alkyl or alkenyl, R₆ represents C₂₋₂₀ alkyl or alkenyl, R₃ and R₄ each represents C₁₋₄ alkyl or -CH₂CH₂OH, and XΘ repre­ sents a counter ion) are useful as miticides with no phy­ totoxicity against fruit trees and vegetables.

Description: This invention relates to a miticide. More particularly it relates to a miticide effective against chemical resisting mites accompanied by no chemical damage on fruit trees and vegetables. Prior Art Recently chemical miticides have been widely applied to various crops including fruits and vegetables. Mites generally breed from early spring to autumn. However recent extension of glass culture has brought about serious damage from mites even in winter. Application of a chemical miticide would restrict the density of mite growth for a period of as long as one month. However, this inhibitory effect is yet insufficient from to viewpoint of culturing period of crops. Thus miticides are repeatedly applied several times in general. The impartation of chemical resistance to mites can be prevented to a certain by avoiding repeated application of one and the same miticide. However such an application is not operated with sufficient care at present. The breeding power of mites is so vigorous that chemical resistances have been frequently become a problem even in the cases where various chemicals are alternately employed. Similar to the cases of bacteriocides and herbicides, it requires approximately ten years to develop a chemical miticide. Therefore impartation of chemical resistances is a serious problem for manufactures. On the other hand, agricultural machine oil is known as a chemical which imparts no resistance. However the concentration of the same wherein it is effective in exterminating mites without any damage to crops is very limited, which makes it practically inavailable for crops including vegetables. Disclosure of Invention Under these circumstances, we have attempted to develop a compound which is effective on chemical-resisting mites accompanied by no chemical damage to crops including fruit trees and vegetables and consequently completed the present invention. Accordingly the present invention provides, for use as a miticide, a composition comprising a weight ratio of 0.1 to 20 of a quaternary ammonium salt of the general formula (I): wherein R₁ and R₂ represent each or an alkyl group having one to four carbon atoms provided that at least one of them represents wherein R₅ represents an alkyl or alkenyl group having four to 22 carbon atoms; and R₆ represents an alkyl or alkenyl group having two to 20 carbon atoms; R₃ and R₄ represent each an alkyl group having one to four carbon atoms or -CH₂CH₂OH; and X ⊖ represents a counter anion. Preferable examples of the counter anion X are Cl, Br or CH₃SO₄. The present invention further provides a miticide solution containing said quaternary ammonium salt as an active ingredient, wherein the active compound is dissolved preferably in water at a concentration of 10 to 2000 ppm in general. The miticide solution of the present invention may further contain conventional miticides. The compound (I) according to the present invention may be prepared in a known manner. For example, it may be prepared by quaternizing a tertiary amine of the general formula (II) with a quaternizing agent such as methyl chloride, methyl bromide or dimethyl sulfate: wherein R₁, R₂ and R₃ are as defined in formula (I). The tertiary amine of the formula (II) may be similarly prepared in a known manner. For example, it may be prepared by directly reacting an alcohol of the formula (III) with methylamine or dimethylamine: wherein R₅ and R₆ are as defined in formula (I). Among the compounds of the general formula (I) according to the present invention, those represented by the formula (IV) or (V): wherein n represents an integer of 3 to 21 and X represents Cl, Br or CH₃SO₄; and wherein n and m represent each an integer of 3 to 21 and X represents Cl, Br or CH₃SO₄; are particularly preferable. In a further aspect the invention provides a method of killing mites. Preferably the miticide of the present invention is applied on crops including vegetables and fruit trees in the form of an aqueous solution or an aqueous dispersion. The miticide of the present invention may be practically applied at a concentration of 10 ppm or above, preferably 100 to 2000 ppm. Within the range as defined above, it exerts an effect of exterminating mites parasitic on broadleaf crops such as soybean and cotton, true grasses such as rice and wheat, vegetables such as cucumber and egg plant and fruit trees such as apple, pear and orange trees without any chemical damage. The miticide of the present invention is effective on various parasitic mites such as Tarsonemidae, Pyemotidae, Eupodidae, Tydeidae, Tetranychidae and Tenuipalpidae. The compound of the present invention exhibits a remarkable synergistic effect when used together with conventional chemical miticides. The effect obtained by simultaneously using these miticide is particularly remarkable on chemical-resisting mites (cf. Example 2). The miticide of the present invention is usually used in a weight ratio of 0.1 to 20 based on chemical miticide components. Best Mode for Carrying Out the Invention The following Examples will be given in order to illustrate the miticidal activity of the compound of the present invention and the synergistic effect obtained by applying the same together with commercially available chemical miticides. Example 1 30 female imagoes of Tetranychus urtiae were inoculated on a kidney bean leaf piece (3 cm x 3 cm) and allowed to stand at 26°C for 12 hours. After confirming the number of survival mites, 0.2 ml portions of the miticide of the present invention, a comparison compound and commercially available miticides each at concentrations of 100 and 1000 ppm were applied on the leaf discs. After allowing to stand at 26°C for 24 hours, dead mites on each disc were counted and the miticidal ratio to the untreated lot (treated with water alone) was determined. This procedure was repeated ten times and the mortality was represented on the average. Table 1 shows the result. Example 2 50 chemical-resisting female imagoes of Panonychus citri were inoculated on a Citrus unshiu sapling aged three years. Then the sampling was allowed to stand in a large phytotron until five mites were observed on each leaf. 1000-fold and 1500-fold dilutions of Dani-cut Emulsion, Acar Emulsion and Omite Wettable Powder were prepared and the compounds (2) and (6) of the present invention were added to each dilution to give a concentration of 500 ppm, thus preparing a dilution mixture. 1000-fold and 1500-fold dilutions of Dani-cut Emulsion, Acar Emulsion and Omite Wettable Powder were employed as such each as a control. 50 ml of a dilution was applied to each sampling. After allowing to stand for seven and 21 days, ten leaves per sampling were collected at random and mites thereon were counted. The miticidal rate was represented based on the data obtained from the untreated lot. This procedure was repeated twice. Table 2 shows the result. The above result suggests that the miticide of the present invention exhibits a remarkable effect on chemical-resisting mites when used together with commercially available miticides. Example 3 The chemical damage to crops caused by the compound of the present invention was examined as follows. 1000 ppm per pot of the compound of the present invention was applied on cucumber and soybean plants on the three- to four-foliate stage until each plant was sufficiently moistened. Then the plant was allowed to stand in a green house. One and seven days after the treatment, the occurrence of chemical damage was examined with the naked eye. For comparison, the comparison compound (1) and Summertime Machine Oil (a commercially available product) were used at the same concentration as that of the compound of the invention. Table 3 shows the result.

Claims: A method of killing mites comprising application of a liquid containing at least 10 ppm of a quaternary ammonium salt of the general formula (I): wherein R₁ and R₂ represent each or an alkyl group having one to four carbon atoms, provided that at least one of them is wherein R₅ represents an alkyl or alkenyl group having four to 22 carbon atoms; and R₆ represents an alkyl or alkenyl group having two to 20 carbon atoms; and R₃ and R₄ each represent an alkyl group having one to four carbon atoms or -CH₂CH₂OH; and X ⊖ represents a counter anion. A method as claimed in claim 1, wherein the liquid is in the form of an aqueous solution or an aqueous dispersion. A method as claimed in claim 2, wherein the liquid contains from 100 to 2000 ppm of the quaternary ammonium salt. A method as claimed in any one of claims 1 to 3, wherein the liquid includes at least one further miticide. A method as claimed in any one of claims 1 to 4, wherein the counter anion X ⊖ is selected from BR ⊖ , C1 ⊖ and CH ₃ SO ₄ ⊖ . A composition for use as a miticide comprising a weight ratio of from 0.1 to 20 of a quaternary ammonium salt of the general formula (I): wherein R₁ and R₂ represent each or an alkyl group having one to four carbon atoms, provided that at least one of them is wherein R₅ represents an alkyl or alkenyl group having four to 22 carbon atoms; and R₆ represents an alkyl or alkenyl group having two to 20 carbon atoms; and R₃ and R₄ each represent an alkyl group having one to four carbon atoms or -CH₂CH₂OH; and X ⊖ represents a counter anion, and at least one further miticide. A composition as claimed in claim 6, wherein the further miticide is selected from summertime machine oil, Kelthane emulsion, Dani-cut emulsion, Acar emulsion and Omite wettable powder. A composition as described in claim 6 or 7 in the form of an aqueous solution or an aqueous dispersion.

Inventors: IWASAKI, TETSUJI 1247, SAIKAZAKI, KURITA, KAZUHIKO 99, FUJISHIRO
Applicants: KAO CORPORATION
Application year: 1986
Main classification: A01N33
IPC codes: A01N33