Effects Of High Temperature On The Develop And Reproduction Of Trichogramma Ostriniae

Trichogramma ostriniae is the natural enemy of Pyrausta nubilalis Hubern.In Liaoning province,T.ostrziniae is used to control second-generation Asian corn borer and plays an important role for its high parasitic rate(usual 80-90%).As temperature is one of the factors affecting insects biological and biochemical characteristics,it could affect the insects feeding,mating,development,reproduction,parasitism,and thus affects the occurrence regularity of insects,population size and distribution.By studying the relationship between temperature and natural enemy insects,it helps to study the population dynamics of natural enemy insects in the field and breeding,low temperature storage and rational release strategy and so on.In addition,in recent years,the frequent occurrences of extreme high temperature make the relationship between temperature and insects(especially natural enemy insects)more complex,thus a more comprehensive and targeted research is needed urgently.Therefore,the T.ostriniae was used in this paper to study its growth and development at different high temperature conditions.The results are as follows:By treating late pupae of T.ostriniae at single 42? with different amounts of time for different groups,the results showed that different amounts of time could significantly affect the parasitism and emergence,causing the increase in the spawning period and decrease in total parasitic number.And the parasitic amount to host eggs and emergence amount of wasps concentrated in the first 3 days under high temperature treatment.Besides,different amounts of time had significant effects on the longevity of female wasps:the longevity of female wasps were significantly short at 3h and 4h treatment.However,there were no significant differences in longevity of male wasps among the treatment groups and control group.The results of study that thermal sensitivity in different development stage of T.ostriniae to high temperature indicated that under 42?,the heat resistance from high to low was:middle pupa>the late pupa>the prepupa>adult stage>larvae>egg.Under 32?(medium heat)treatment to whole stage of maternal T.ostriniae,the spawning amounts of maternal wasps were significantly less;the amounts of emergence were not significant less or more if the temperature was recovery from heat;the continuous moderate high temperature treatment to T.ostriniae in only oviposition period could cause significant decrease in emergence rates.