2000 年 44 巻 4 号 p. 235-239
Seasonal occurrence of Tetranychus kanzawai Kishida and its predators in the border vegetation, Clerodendrum trichotomum and Akebia quinata, of pea-watermelon fields were investigated in Wakayama Prefecture, southwestern Honshu, Japan during 1993-1994. There were two peaks in the population density of T. kanzawai on C. trichotomum: one was in April-May and the other in November. However, the density was low in summer when predacious mites (mainly Amblyseius eharai and A. sojaensis) occurred. The application of cypermethrin caused a resurgence in T. kanzawai on C. trichotomum during summer and autumn, showing that the predators had suppressed the mite population. Oligota kashmirica benefica and cecidomyiid, Feltiella sp., and Scolothrips takahashii were the predominant predator species of T. kanzawai when its density was high on C. trichotomum and A. quinata.