Diapause characteristics of the Kanzawa spider mite Tetranychus kanzawai Kishida, in pea fields of central Wakayama Prefecture, Japan.
The diapause status was studied of Tetranychus kanzawai Kishida, occurring in pea fields and on non-cultivated hosts along fields in central Wakayama Prefecture, Japan. The proportion of diapausing females on peas and the non-cultivated evergreen host, Akebia quinata (Thunb.), increased through autumn, reaching a peak of 60% in December, but declined thereafter. In November, a higher proportion of diapausing females was found on another non-cultivated deciduous host, Clerodendrum trichotomum Thunb., than on the above two hosts. This earlier increase on C. trichotomum was due to the host defoliation. The diapause percentage of T. kanzawai at 16°C and 20°C was close to 100% at daylengths shorter than 10 h. The critical daylength induction was between 10 and 11 h.