Multiparasitism Of Trichogramma Dendrolimi And Trichogramma Ostriniae On Antheraea Pernyi Eggs, And The Studies Of Their Cooperative Breeding

Currently the eggs of Chinese oak silkworm,Antheraea pernyi,are among the best factitious hosts for mass production of Trichogramma parasitoids.However,the thick and hard chorion of large egg of A.pernyi became limiting factor for some parasitoids which were leaved and unable to form emergence hole to escape,such as T.ostriniae.T.dendrolimi is among a few parasitoids which have been able to emerge from A.pernyi egg successfully.In the present study,we evaluated the possibility to enhance adult emergence of T.ostriniae by utilizing emergence holes made by T.dendrolimi during multiparasitism on host egg of A.pernyi,and other biological parameters to evaluated the possibility to rear T.ostriniae via multiparasitism with T.dendrolimi on eggs of A.pernyi.The main results obtained as followed.1.The influence of introducing parasitoid ways on synparasitism of both Trichogramma species on A.pernyi eggs.The different ways of introducing parasitoid have a significant effect on the emergence of adult T.ostriniae.In terms of the parasitism rate of large eggs of A.pernyi,simultaneous access to T.dendrolimi and T.ostriniae was 24 h,the parasitism rate was 80.9%,which was significantly higher than the parasitization rate at the time of introducing parasitoids.The total number of emergence of adult T.ostriniae also showed obvious advantages in the multiparasitism,reaching 75.9 and 3.4 respectively.Therefore,in the use of large eggs of A.pernyi multiparasitism two Trichogramma should take the multiparasitism way.In addition,no T.ostriniae emerged when T.ostriniae was parasitized on eggs of A.pernyi alone.2.The influence of different condition on synparasitism of both Trichogramma species on A.pernyi eggs.The temperature had a significant effect on the co-evolution of Trichogramma species.The parasitism rates of two Trichogramma species on A.pernyi eggs will decrease with the increase of temperature,and the high temperature will affect the growth of two Trichogramma species.With different degrees of influence,the suitable temperature range for breeding two Trichogramma species is between 23-26 °C.At the temperature of 26°C,all biological indicators were high,and the number of T.ostriniae was 3.8.Therefore 26 °C is the optimal temperature condition for the synergistic breeding of Trichogramma species.Different humidity conditions showed little difference between two Trichogramma species.The changes in humidity had no regular changes in the parasitism rate,and the emergence rate decreased with increasing humidity.When the humidity was 80% and 90%,there was no significant difference in the number of T.ostriniae,and the number of T.ostriniae that emerged was higher.Especially at the humidity of 80%,the number of T.ostriniae reached the maximum.In terms of illumination,the parasitism rates of two Trichogramma species on A.pernyi eggs decreased with the shortening of the illumination time,and the illumination time had no significant effect on the emergence rate.However,under the condition of 24 hours,the emergence rate was the highest.The total number of Trichogramma reached the maximum,which was significantly higher than that in the dark conditions.The increase of the visible light time favored the emergence of the two Trichogramma species.For the T.ostriniae,there was no significant difference in the number of T.ostriniae under 24 h total light and 10 h light conditions.The number of T.ostriniae emerged reached maximum under 24 h light conditions.Taken together,the selected optimum temperature,humidity,and light conditions are randomly combined to form six different environmental conditions that allow for the biology of two Trichogramma species under six different environmental conditions.The index analysis showed that the temperature of 26°C,humidity 80% and light condition 24L: 0D resulted in the highest number of T.ostriniae.3.Effects of different ratios on the coordinated breeding of T.dendrolimi and T.ostriniae.Regardless of one,three,or five A.pernyi eggs were provided,the number of T.ostriniae in the single egg was significantly different from the total number of T.ostriniae.When the ratio of was 1:5,the number of T.ostriniae was the best,respectively,and when one egg was provided,the number of emerged adult of T.ostriniae increased to 17.3.Taken together,during the production process,T.dendrolimi: T.ostriniae: A.pernyi eggs are bred at a ratio of 1:5:1,which can be better applied to the larvae of T.dendrolimi and T.ostriniae.4.In the process of breeding,the optimal mixing ratio of parasitized eggs and fresh A.pernyi eggsWith the increase of fresh tussah eggs,the parasitization rate decreased significantly.The parasitic rate reached 90% when five fresh eggs were introduced,and the parasitic rate was only 72% when 20 fresh eggs were introduced.When 5 eggs were inserted,the total number of Trichogramma were 80.9.The highest number of T.ostriniae reaching 18.3,which was significantly higher than the other treatments.Therefore,in the process of breeding,each parasitized egg provided with 15 fresh tussah eggs was the best mixing ratio,which can breed the most T.ostriniae.5.Effect of egg surface treatment breeding T.ostriniae on A.pernyi eggsThe parasitism rates of the A.pernyi eggs treated with pyrolysis solution were reduced whether T.ostriniae alone parasitized A.pernyi eggs or not.5 Trichogramma parasitism of parasitic eggs is only 35%.In the aspect of eclosion rate,T.ostriniae was able to normalize emergence of Trichogramma eggs in the tussah eggs treated with pyrolysis solution,but no eclosion was observed in A.pernyi eggs washed with only water.Judging from the total number of T.ostriniae and total emerging adults of T.ostriniae,the quinqueflies eggs treated with the five T.ostriniae alone were treated with pyrolysis solution and the highest was 6.7.There was no difference with 1 untreated egg.However,the parasitic rate of the untreated eggs was significantly higher than that of the flaconine solution,and the parasitic eggs reached 80%.Therefore,T.ostriniae should be bred using A.pernyi eggs washed only with clean water.Through the biological parameters of multiparasitism of two Trichogramma species on host egg of A.pernyi under different environmental conditions and ratios.Under the environmental conditions of temperature 26°C,humidity 80% and light for 24 hours,the parasitism eggs were obtained at a ratio of 1:5:1,and after the emergence of Trichogramma.A total of 15 fresh tussah eggs per parasite egg can be used to achieve large-scale breeding of Trichogramma.This study tentatively established that it is feasible to co-immit larvae of Trichogramma chilonis and Trichogramma dendrolimi to improve the emergence rate.The results of this study had provided useful information on feasibility of mass production of T.ostriniae via multiparasitism with T.dendrolimi on large eggs of A.pernyi and provides a new way on feasibility of mass production of T.ostriniae on large eggs of A.pernyi.