The Spray Records of Insecticides and Acaricides to the Kelthane Resistant Mite in the Tea Fields, Kyoto Prefecture

Abstract

We reported in the previous paper (1969) the distributions of resistant mites, Tetranychus kanzawai KISHIDA, to Kelthane (1, 1, Bis-(p-chlorophenyl) 2, 2, 2-trichloroethanol) and Estox (0, O-Dimethyl, S-(1-methyl-2-ethylsulfinyl)-ethyl phosphorothioate) in the tea fields of Kyoto prefecture. In this survey, the spray records of insecticides and acaricides to the Kelthane resistant mite in the tea fields of Yamashiro town southeast in Kyoto prefecture were investigated.1. In the research fields, the spraying of Kelthane for the control of tea red spider mite began in 1961-'65.2. At the beginning use of Kelthane, organophosphorus compounds such as EPN and Phenkapton were generally used for the control of mites, and the effects of these chemicals including Kelthane showed good results.3. In some tea fields, however, the effect of Kelthane on the mites decreased in 1965-'66. These phenomena in each field were observed after 3-4 years from the beginning use of Kelthane, and the spraying frequency of Kelthane in this duration was about 20 to 30 times or more.According to the above mentioned results and the previous paper (1969) by the authors, the relationship between the spraying frequency of Kelthane and the resistivity of mites to Kelthane was as follows, i. e., the mites lived in the fields sprayed less than 10 times of Kelthane showed non-resistance, about 20 times showed low resistance, and about 30 times or more showed high resistance (R/S ratio about 50) to Kelthane, respectively.4. During the beginning use of Kelthane to the decrease of its effect, many kinds of organophosphorus and chlorophenyl compounds had been used for the control of mites and other tea pests. In this duration, however, Kelthane was used most frequently as compared with the other chemicals.5. In 1967, Kelthane was continued to use as before for the control of the Kelthane resistant mite because there were no more effective acaricides, and resulted in a less effect for the control of this strain.Acricid of dinitro compound may be effective to the control of Kelthane resistant mite. However, this chemical gives an injury on the young leaves of tea, therefore, it must not be used in the growing season of young leaves.6. The Kelthane resistant mite also indicated the resistance to some organophosphorus compounds, therefore, the mites in the research fields may gain a multiple resistance between organophosphorus compounds and Kelthane, but the presence of cross resistance was not cleared.7. As a result of the survey, it was considered that the development of the Kelthane resistant mite was due to a high frequency of spraying of Kelthane.