The Effects Of Host And Ascovirus (HvAV-3h) On Development And Parasitical Effecency Of Microplitis Prodeniae Rao&Kurian (Hymenoptera:Braconidae)

In order to prevent population extinction,parasitoid needs to find the most suitable hosts.During this period,parasitoid usually carries some pathogens.It may play a vital way in the transmission of insect pathogenic microorganisms.In this study,firstly,the morphological and behavior of Microplitis prodeniae Rao & Kurian were observed,and M.prodeniae was quickly identified by co I gene.Secondly,the host selection experiments were conducted to determine which host was suitable for M.prodeniae.Spodoptera exigua and Spodoptera litura were suitable hosts.The effective threshold temperatures and effective accumulated temperatures of M.prodeniae were compared between different hosts.The growth and development,generations,survival rate and life expectancy of parasitic wasp were studied in S.exigua and S.litura under different temperatures.At last,ascovirus Hv AV-3h effected on the parasitical effcency of M.prodeniae were researched.The results were as follows:(1)M.prodeniae was studied in morphological character and behavior.The co I gene was analyzed the phylogenetic status of M.prodeniae.The potential host experiments for M.prodeniae were done,and the parasitic rates were 65.5%,44.9% and 0.0% to S.litura,S.exigua and Helicoverpa armigera,respectively.The results indicated that M.prodeniae preferred to parasitic 2 and 3 instar larvae of S.exigua,the parasitic rate were 65.0% to 70.4%.215.28 d·? and 228.17 d·? in S.litura and S.exigua,respectively.(2)There was no significant difference in the growth and development of M.prodeniae between S.litura and S.exigua.When the host was S.litura,the pre-adult of M.prodeniae was 12.8 d to 37.1 d.When the host was S.exigua,the pre-adult of M.prodeniae was 12.6 d to 35.7 d.The parasitic rate of M.prodeniae in S.litura was 65.5% significantly higher than in S.exigua 52.1% at 27?.The rate of cocooning of M.prodeniae in S.exigua was higher at21?.The development initiation temperatures of M.prodeniae in S.litura and S.exigua were 11.94 ? and 11.23 ?,respectively.The effective accumulated temperatures were(3)M.prodeniae carrying Heliothis virescens ascovirus 3h(Hv AV-3h)parasitized on two kind hosts had the similary lethality rate.The host infection rate of parasitized S.exigua was31.7% significantly higher than that parasitized S.litura 16.8%.The infection rate increased with the increase of temperature.The highest host infection rate was 38.57%,and the higher parasitism rate was 37.9% at 30?.Compared with the infection host,parasitic wasp was biased towards healthy host.The results provided scientific basis for the large-scale reproduction and field release of M.prodeniae.At the same time,the results provided a theoretical basis for M.prodeniae natural as enemy insect to make biological control some Lepidoptera pests,too.