1968 Volume 12 Issue 1 Pages 18-22
In the previous paper by the author, the occurrence of the tea red spider mite, Tetranychus kanzawai KISHIDA, resistant to Phenkapton in 1961-1962 and to Estox in 1964 in some tea fields in Shizuoka-Pref. were reported. In this paper, the resistance response of mites, collected from many districts of tea growing areas in Japan, to Phenkapton (0,0-Diethyl S-(2,5-dichlorophenylthio)-methyl phosphoroditioate), Estox (0,0-Dimethyl S-(1-methyl-2-ethylsulfinyl)-ethyl phosphorothioate) and Kelthane (1,1-Bis-(p-chlorophenyl) 2,2,2-trichloroethanol) were investigated. From the results in 1965-1966,the resistance response of mites to Phenkapton, Estox, and Kelthane were classified to the resistant and the susceptible groups. The LC50 values of each resistant and susceptible of mites to these chemicals were shown as follows : Phenkapton ; resistant mites 165.6±34.0 ppm, susceptible mites 1.2±0.6 ppm, RS ratio (R/S) 138.0. Estox ; resistant mites 1182.3±510.2 ppm, susceptible mites 7.2±2.0 ppm, RS ratio 164.2. Kelthane ; resistant mites 234 ppm, susceptible mites 3.8±1.9 ppm, RS ratio 61.6. The resistance of these mites to each chemical may be divided into the three types. The first type is susceptible to Phenkapton, Estox, and Kelthane, the second type is resistant to Phenkapton and Estox, but the susceptible to Kelthane, and the third type is resistant to all three of these chemicals. The mites belonging to the first type were discovered in Saitama-Pref. in Kanto, Kagawa-, Tokushima- and Kochi-Pref. in Shikoku, and Miyazaki-, Kagoshima-Pref. in Southern Kyushu districts, and the second type of mites widely distributed in Shizuoka-, Aichi-, Mie-, Shiga- and Nara-Pref. in Tokai-Kinki and Fukuoka-, Saga-Pref. in Northern Kyushu districts. The third type of mites were very few, and this type was discovered in Kyoto-Pref. From the correlation coefficient concerning the LC50 of three chemicals, it may be said that the cross-resistance is present between Phenkapton and Estox, but it was not observed between Kelthane and Phenkapton or Estox.
