松毛虫赤眼蜂滞育诱导及解除条件研究

【目的】以柞蚕Antheraea pernyi卵为繁殖寄主,对松毛虫赤眼蜂Trichogramma dendrolim滞育诱导及解除条件进行研究,以解决赤眼蜂工厂化生产和大面积应用中面临的的中、长期储存问题。【方法】通过观测不同发育阶段(寄生柞蚕卵在26℃培养40、96和144 h)、滞育诱导温度(10、13和16℃)和诱导时间对松毛虫赤眼蜂滞育的影响,确定松毛虫赤眼蜂滞育诱导条件;通过观测滞育诱导温度和滞育后的贮藏温度对滞育解除的影响,确定松毛虫赤眼蜂滞育解除条件。【结果】在松毛虫赤眼蜂的不同发育阶段对其进行持续的低温刺激均能使其导入滞育,但以小幼阶段(26℃培养40 h)开始效果最佳,寄生卵在26℃培养40 h后,转入10℃和13℃下连续诱导31 d,滞育率可达100%和99.12%。滞育诱导温度和滞育后的贮藏温度对松毛虫赤眼蜂解除滞育所需时间和解除滞育后的羽化出蜂率有较大影响,10℃诱导滞育后置于1℃冷藏的赤眼蜂解除滞育所需时间最短,解除滞育后的羽化出蜂率和单卵出蜂数更高,更耐储存。此条件下冷藏约30 d开始打破滞育,在正常发育下温度下羽化出蜂,60 d羽化出蜂率达到95.24%,冷藏4个月后羽化出蜂率仍在60%以上,单卵出蜂数高于50头。【结论】松毛虫赤眼蜂最佳滞育诱导条件为26℃培养40 h后,转入10℃连续低温诱导31 d;最佳滞育解除条件为1℃低温储存,但储存期不能超过4个月。

Research on the induction and termination of diapause in Trichogramma dendrolimi

Objectives] To determine the optimum conditions for the induction and termination of diapause in Trichogramma dendrolimi in Antheraea pernyi eggs. Methods] The effects of age （parasitoids developed for 40, 96 and 144 h after parasitization at 26℃）, temperature （10, 13 and 16℃）, and low temperature exposure period on diapause rate were investigated to determine the optimum conditions of diapause indication. The emergence rate, emergence synchronism and number of wasps emerged per Antheraeapernyi egg post diapause termination after cold storage at different temperatures for different periods were investigated to determine the conditions required for the termination of diapause. The effects of diapause inducing temperatures on diapause termination were also studied. Results] Diapause was induced in insects of different ages by exposure to constant low temperatures, but the highest diapause rates （100% and 99.12%, respectively） were achieved when young larvae （26℃ for 40 h） were exposed to 31 days of low temperature at 10 and 13℃ Diapause termination of T. dendrolimi, and its post-diapanse emergence was affected by both diapause induction temperature and cold storage temperature. Diapausing prepupae that were inducted at 10℃ and then stored at 1℃ had a shorter diapause breaking time, a higher emergence rate, and a longer storage period. These pupae stared to emerge normally, when transferred to 26℃ after being stored at 1 ℃ for 30d. After being stored for60 d, the emergence rate reached 95.24% and the emergence rate was higher than 60%. More than 50 wasps emerged per host egg after storage for 4 months. Conclusion] The optimum conditions to induce diapause in T. dendrolimi consisted of keeping the parasitoids at 26℃for 40 h, and then moving them into 10℃ for 31d; the optimum diapause breaking conditions were storing diapansing prepupae at 1 ℃, however the storage period should be not exceed 4 months.