Seasonal egg parasitism of phytophagous stink bugs in a soybean field in Fukuoka

Eggs and adults of phytopahgous stink bugs were subjected to a census at intervals of 1 week in a soybean field in Fukuoka during the period from late June to mid October in 1984. Eggs and adults of four stink bugs, Riptortus clavatus, Piezodorus hybneri, Eysarcoris guttiger and Megacopta punctissimum were detected in the census field. Egg parasitism of these stink bugs involved four parasitoid species: Ooencyrtus nezarae collected from all the four host species, Telenomus sp. from P. hybneri and E. guttiger, Ooencyrtus sp. from R. clavatus and P. hybneri, and Gryon hakonensis from R. clavatus . Although parasitism
of host eggs by G. hakonensis and Ooencyrtus sp. was found only during the period from late July to early August, parasitism by O. nezarae and Telenomus sp. was continuously observed throughout the census period. This seasonal pattern of parasitism by the latter two species may be ascribed to the reproduction in the census field associated with their short generation times and the continuous host supply for a long period.