The incidence of diapause in two species of spider mite, Tetranychus urticae and T. kanzawai, was determined for populations derived from various regions in East and Southeast Asia, at 3 temperatures under short-day conditions. The distribution of T. urticae was locally limited. It has been known that the T. urticae populations in northern Japan have a high capacity for diapause and the mites show a clinal decrease in diapause capacity. However, all populations examined in this study, including those from southern Japan, had very low capacity for diapause. T. kanzawai was one of the most common spider mites over the entire East Asia. In East Asia the mites occurred not only on cultivated plants but also on wild plants, but in Southeast Asia they were observed only on cultivated plants. Most populations derived from Japan (except those from the Okinawa Islands, which had low diapause capacity), Korea and South-central China had very high capacity for diapause, whereas populations from Thailand showed low incidence of diapause. The Taiwanese populations had very diversified diapause percentage among local populations. There was a conspicuous decrease in diapause expression with increasing temperature in populations from the Tanegashima and Yakushima Islands, China, Vietnam and Indonesia. Contrary to our expectation, the tropical populations from Indonesia and Philippines maintained a high capacity for diapause. Thus, T. kanzawai did not show any explicit clinal decrease in diapause capacity, as was observed in T. urticae.

View full abstract

A new species of oribatid mite of the family Autognetidae Grandjean, 1960, Conchogneta iranica n. sp., is described from Mazandaran province, Northern Iran. Also an identification key to the Conchogneta species is given.

View full abstract

Between 2001 and 2006, we investigated native phytoseiid mites occurring in greenhouses where vegetable crops were cultivated under pest control programs utilizing natural enemies in Kochi prefecture. Nine phytoseiid species were collected. The most common species in the coastal plane area were Neoseiulus barkeri Hughes and Euseius sojaensis (Ehara). However, Amblyseius eharai Amitai and Swirski were the most common species in the mountainous area. Three species of A. eharai, E. sojaensis and A. tsugawai Ehara were observed more frequently on green pepper than on eggplant. Possible reasons for recent frequent observations of phytoseiid mites on greenhouse crops are discussed.

View full abstract

We investigated the prey consumption and oviposition rates of six native phytoseiid mites, Neoseiulus barkeri Hughes, Euseius sojaensis (Ehara), Amblyseius tsugawai Ehara, Proprioseiopsis nemotoi (Ehara and Amano), Gynaeseius liturivorus (Ehara) and A. eharai Amitai and Swirski, occurring in greenhouses in Kochi prefecture. These values were compared with those of N. cucumeris Oudemans, a commercial biological control agent. First instar larvae of Thrips palmi Karny were provided as prey for predacious mites. The results showed that G. liturivorus exhibited excellent prey consumption and oviposition rates as 12.2 larvae/day and 6.5 eggs/day, respectively, whereas those of N. cucumeris were 3.9 larvae/day and 2.2 eggs/day, respectively. A. eharai also showed a higher prey consumption rate (5.8 larvae/day) than N. cucumeris. Four other native phytoseiid species also consumed T. palmi larvae, but the prey consumption and oviposition rates were lower than N. cucumeris. In conclusion, both G. liturivorus and A. eharai were considered as promising candidates for biological control agents of T. palmi.

View full abstract