Life-history traits of the Kanzawa spider mite Tetranychus kanzawai (Acari: Tetranychidae).

Life-history traits of the Kanzawa spider mite, Tetranychus kanzawai, were assessed and compared with those of the closely related species, T. parakanzawai.This was done by determining the intrinsic rates of natural increase, r m , of three strains of T. kanzawai and one strain of T. parakanzawai, on leaf discs from each of the four host plants (collected plants) as well as one of suitable hosts for T. kanzawai, mulberry.The r m -values of the three T. kanzawai strains varied largely from 0.187/day to 0.283/day, and the r m 's on the collected hosts (tea, hydrangea and Japanese pear) were 0.043-0.096/daylower than on mulberry.The r m of the T. parakanzawai strain was only 0.008/day lower on the collected plant (kudzu vine) than on mulberry.These results seem to suggest that tea, hydrangea and Japanese pear are poor-quality plants for T. kanzawai when compared to their performance on mulberry.