沖縄に分布するTetranychus属ハダニ 9種に対する各種農薬の殺虫効果

抄録

The insecticidal effect of 28 commercial agrochemicals on nine Tetranychus species inhabiting Okinawa was examined under laboratory conditions. The two-spotted spider mite, T. urticae (green form), was resistant to the majority of tested agrochemicals including organophosphate insecticides, synthetic pyrethroid insecticides, and pyrazole acaricides. Some new specific acaricides and spiracle-blocking insecticides were effective against this species. Synthetic pyrethroid insecticides, pyrazole acaricides, and several other chemicals were less effective against a local population of the Kanzawa spider mite, T. kanzawai, but they were effective against another population of this species. While T. okinawanus and T. piercei were susceptible to the majority of the specific acaricides, some of the non-specific insecticides were less effective against these species. The other five species (T. neocaledonicus, T. ludeni, T. pueraricola, T. parakanzawai and T. phaselus), which are not dominant on crops in Okinawa, showed susceptibility to most of the agrochemicals tested, except a few non-specific insecticides. The present results suggest that T. urticae (green form) and T. kanzawai would be more difficult to control than other Tetranychus species in Okinawa using agrochemicals, even though the frequency of occurrence of T. okinawanus and T. piercei on crops is currently higher than that of the two species.