The Suitability Compare Of Ostrinia Furnacalis For Two Trichogrammatidae Species

Ostrinia furnacalis is the most important pest for the drought crops such as corn and broomcoen,the biological control for this pest is to release Trichogrammatidae species,T.ostriniae and T.dendrolimi are endophagous parasitoids of insect eggs,and they can be used to control O.furnacalis.The control effect of T.ostriniae is universally accepted,while it is different for T.dendrolimi due to different geographic area,to identify the reason for control effect on O.furnacalis by T.ostriniae and T.dendrolimi,we designed several experiments to analysis and exploration the suitability of O.furnacalis and related factors for both species,the results are as follows:(1)The comparation of suitability for T.ostriniae and T.dendrolimi within 3 kinds of host shows that the differences are the number of parasitized eggs and emerged wasps per emergence hole.The parasitized eggs parasitized by T.ostriniae are more than that of T.dendrolimi in the same stage of host,with host age increasing,the number of parasitized eggs of both species are significantly decreased.The number of emerged wasps per emergence hole of T.ostriniae are related with host age,while the situation does not go with T.dendrolimi,the number of emerged wasps per emergence hole of T.ostriniae is more than T.dendrolimi in 48 h old host,there is not a significance beyond 48 h.(2)The consuming time of several main behaviors of T.ostriniae and T.dendrolimi shows that it always goes that the ovipositing time of T.ostriniae is longer than that of T.dendrolimi in any kind of host,there is not a difference between 0-24 h and 24-48 h old host ages,but the consuming time of several main behaviors of T.ostriniae on 48-72 h old host are longer than that on 0-24 h and 24-48 h old,The same situation goes for T.dendrolimi.(3)The result of offspring parasitized once by T.ostriniae include 0,1,2 individuals,the proporation of 1 individual and 2 individual are adjacent.The result of offspring parasitized once by T.dendrolimi also include 0,1,2 individuals,but the proporation of 1 individual is main,with host age increased,the proporation of 0 individual of both species improved,the proporation of 1 individual of T.ostriniae increased and later decreased,and the proporation of 2 individual are opposite,while the proporation of 1 individual of T.dendrolimi is always the most.(4)The parasitized eggs are significantly different in 3 kinds of host radiated with 300 Gy of 60CO between T.ostriniae and T.dendrolimi,and the eggs parasitized by T.ostriniae are more than T.dendrolimi,same here with 400 Gy except the situation under 48-72 h old host.The radiation significantly decreased the parasitized eggs of T.ostriniae on 0-24h old host,while increased that of 48-72h old host of T.dendrolimi.(5)By means of AO/EB dying,we find there are dead larvae in host after parasitized 24,36,48 h,and the percentage of both live larvae decreased with the host age increased.The difference of suitability on O.furnacalis eggs between T.ostriniae and T.dendrolimi are associated with parasitic behaviors and eggs per parasitization.Host age has a significant influence on suitability.Under the 60Co,the suitanility of T.dendrolimi improved,all the results have a guidance for biological control.