Overwintering Characteristics Of Main Parasitods On Chilo Suppressalis In Yang Zhou Area And The Research And Application Of Cotesia Chilonis

Chilo suppressalis,one of the most important pest on rice,has been aggravated in many provinces and cities recently.The Cotesia chilonis(Munakata)is one of the main larval parasitoids of Chilo suppressalis(Walker),in natural environment.This parasitoid can only parasitize on C.suppressalis(Walker)in the field,it currently exists in many countries and regions around the world.In order to study the resources of biological control in C.suppressalis,in this paper we investigated the characteristics of C.suppressalis and its parasitoids in Yangzhou area;for evaluation the control ability of the important nature enemy of C.suppressalis—C.chilonis,the important biology of C.chilonis was also studied in this paper.For the current damage of C.suppressalis,several different pesticides were selected,and C.chilonis was choosen for the control of C.suppressaliss in field.The main results are as follows:1.We investigated the overwintering characteristics of C.suppressalis and its parasitoids in the field around Yangzhou area from August 2017 to May 2018.The results showed that the diapause intensity of C.suppressalis reached the highest on November 13,2017 in Yangzhou area.Chelonus munakatae(Munakata),Eriborus sinicus(Holmgren)and C.chilonis were three main parasitoids of overwintering C.suppressalis larvae.And all of them could complete the generationssafely in C.suppressalis,andC.chilonis was the most important parasitic wasp in overwintering C.suppressalis larvae.Although three kinds of parasitoids possessed different overwintering characteristics,their overwintering characteristics correlated closely to the overwintering characteristics of C.suppressalis.2.Biological experiments showed that emergence of C.chilonis had obviously rhythm,and the emergence was concentrated from 6 to 12 a.m.Compared with adults of C.chilonis with non-feeding nutritions,adults with feeding nutritions obviously were prolonged their lifespan.And the prolongation effect of each treatment were:10%pollen liquid>10%honey water>clear water>non-feed nutritions.3.The experiment of parasitic biologies of C.chilonis exhibited that different host density of C.suppressalis had the effects on of parasitic characteristics of C.chilonis.When the density of host increased,the parasitic rate of C.chilonis and the density of C.suppressalis were negative acceleration curve,and this curve accorded with Holling functional response type ?.When female adults of C.chilonis parasitized C.suppressalis,they didn't parasitized all eggs on one host,but repeatedly parasitized on multiple hosts,the total number of eggs laid by singe female adults of C.chilonis increased with the times of parasitizion However,with the number times of parasitizion,the number of eggs laid by female adults of C.chilonis decreased,and the number of eggs produced in the first four times was significantly higher than that in the last third times.Moreover,the parasitic rate of non-diapausing C.suppressalis larvae by C chilonis was slightly higher that of diapausing C.suppressalis larvae.Therefore the diapausing C.suppressalis also can be used in the reproduction of C.chilonis.4.The results of different green pesticides and C.chilonis control experiments in the field showed thatC.chilonis had significant control on the effect of C.suppressalis,and the control effect of C.chilonis could reach up to 39.18%after 28 d,when C.chilonis were released.And the control effectof C.chilonis could maintain,and after 42 d the control effect was still 12.25%.At the same time,the effect of 7 kinds of pesticides on the C.suppressalis ranking from highest to the lowestwas 10 billion/microliter of Empedobacter brevis suspension concentrate(600 ml/667 m2)>8000 IU/microliter of Bacillus thuringiensis suspension concentrate(125 ml/667 m2)>10%cyanamide amide suspension concentrate(20 ml/667 m2)>20%Triazophos emulsifiable concentrate(100 ml/667 m2)>200 g/L chlorantraniliprole suspension concentrate(10 ml/667 m2)>25%dimehypo t(200 g/667 m2)>5%emamectin benzoate emulsifiable concentrate(4 g/667 m2).