The Study on Diapause Induction in Anastatus japonicus Ashmead

As the major natural enemy of stink bugs,A.japonicus is very effective in suppressing stink bugs populations,and has been commercially used in biological control of stink bugs.In order to accurately control the adult emergence of A.japonicus and improve its control efficacy,the research on the diapause induction of A.japonicus were performed in this study under different temperatures and development stages.The results indicated that A.japonicas diapause as pre-pupa.Low temperature and short day length could induce diapausein A.japonicus from egg to 3rd instar larva.When the egg,1—2 instar and 2—3 instar larva of A.japonicus were exposed to a photoperiod of 6 L:18 D at 17℃,they would enter into diapause as pre-pupa,the incidence of diapause were 76.37%,81.51%and 60.28%,respectively.There was no significant difference in the diapause incidence between treatment with egg and 1—2 instar larva,but their diapause incidence was significantly higher than treatment with 2—3 instar larva.When 1—2 instar and 2—3 instar larva of A.japonicus were exposed to 11℃or 14℃,the diapause incidence decreased to less than 20%.Temperature plays a crucial role in A.japonicus diapause induction.The diapause incidence is different when A.japonicus were exposed to 17℃with different development stage.In this study,the higher diapause incidence was achieved in treatment with egg and 1—2 instar larva of A.japonicus under photoperiod of 6 L:18 D at 17℃.