黑胸茧蜂与寄主关系的研究

Relationships between Bracon nigrorufum (Cusbman) and its hosts

黑胸茧蜂除寄生根红铃虫、梨小食心虫外，豆荚螟是又一发现的新寄主。黑胸茧蜂对棉红铃虫寄生率高，豆荚螟、梨小食心虫依序次之。在湖北，黑胸茧蜂越冬代于5月上、中旬开始羽化，5月中、下旬寄生第二代梨小食心虫，6月中、下旬越冬代大量羽化集中寄生春大豆上第二代豆荚螟，7月上、中旬转移至棉田寄生第一代棉红铃虫，8月上、中旬又向棉田四周的夏大豆田转移寄生第三代豆荚螟，9月上、中旬迁回棉田寄生第三代棉红铃虫直至越冬。

Results from lab experiments and field observation show that Etiella zinckenella (Treitschke) is a newly found host of Bracon nigrorufum (Cushman), besides the known hosts──Pecrtinophora gossypiella (Saundrs) and Grapholitha molesta (Busck). The parasihzation on P gossypiella (Saundrs)is the highest and which on G.molesta(Busch) is the lowest.Every year in Hubei province, on early-May, the hibemating generation of B nigrorumfum (Cushman begin to emerge and parasihze the 2nd generation of G. molesta (Busch). Most of the hibernating generation emerge on mid-and late-June,then attack the 2nd generation of E. zinckenalla (Treitschke)which infest the spring soybean. On eariy-and mid-July, the wasp migrate to cotton field and parasitize the Ist generation of P.gossypiella Saundrs. On early and mid-August, the wasp fly to summer soybean field and attack the 3rd generation of E.zinckenella (Treitschke), then come back to cotton field and parasitize the 3rd generation of P gossypiella (Saunders) until overwintering time.