紫外处理梨小食心虫卵对暗黑赤眼蜂寄生和羽化的影响

【目的】研究暗黑赤眼蜂Trichogramma pintoi Voegele对经紫外线照射处理的梨小食心虫 Grapholita molesta (Busck)卵的寄生效果， 确定处理寄主卵的最佳紫外强度和处理时间， 为利用小卵大量饲养赤眼蜂时寄主卵的处理和保存提供方法。【方法】初羽化12 h内的暗黑赤眼蜂分别寄生经不同强度紫外灯处理不同时间的梨小食心虫卵， 观察其寄生状况， 并统计寄生率和羽化率， 与对未经紫外处理的梨小食心虫卵的寄生率和羽化率作比较。【结果】暗黑赤眼蜂对经紫外照射的梨小食心虫卵的寄生率明显下降， 且随着紫外光强度的增强和紫外处理时间的延长， 影响强度增大。紫外处理梨小食心虫卵后， 暗黑赤眼蜂羽化率变化不大， 用15W紫外灯1-2 h或30W紫外灯照射1 h后， 暗黑赤眼蜂羽化率有所提高， 均在80%以上， 但在紫外照射3 h后， 羽化率明显下降。【结论】处理梨小食心虫卵时的紫外光强度及紫外处理时间对暗黑赤眼蜂寄生梨小食心虫卵的寄生效果均有一定的影响。实验室利用梨小食心虫卵大量繁殖暗黑赤眼蜂时， 宜采用15W 1 h紫外照射， 既能杀死寄主卵的胚胎， 又不会对暗黑赤眼蜂的寄生效果产生明显的不利影响。

Effect of UV treatment of Grapholita molesta ( Lepidoptera: Tortricidae) eggs on parasitism and emergence of Trichogramma pintoi ( Hymenoptera: Trichogrammatidae )

Aim] Experiments were conducted to evaluate the effects of ultraviolet treatment of Grapholita molesta(Busck) eggs on parasitization and emergence of Trichogramma pintoi Voegele.The optimal ultraviolet intensity and irradiation time to treat G.molesta eggs were determined in order to provide the treatment and storage means of host eggs in mass rearing of T.pintoi.Methods] T.pintoi adults within 12 h after emergence were supplied to parasitize G.molesta eggs which were irradiated by various ultraviolet intensities for different time,the parasitization performance was observed,and the parasitization rate and emergence rate were calculated and compared with that of T.pintoi parasitized G.molesta eggs not irradiated by ultraviolet.Results] The results showed that the parasitization rate of T.pintoi significantly decreased when T.pintoi parasitized the G.molesta eggs which were irradiated by ultraviolet.With the enhancement of ultraviolet intensity and irradiation time,the parasitization rate significantly decreased,while the emergence rate had little change.When the G.molesta eggs were irradiated for 1-2 h by 15 W ultraviolet light or irradiated for 1 h by 30 W ultraviolet light,the emergence rate increased over 80% when compared to the control.But when G.molesta eggs were irradiated by ultraviolet for 3 h,the emergence rate decreased obviously.Conclusion] Parasitism and development of T.pintoi could be affected by ultraviolet intensity and treatment time.Therefore,irradiation with ultraviolet light of 15 W for 1 h is suggested in mass rearing of Trichogramma by small eggs in the laboratory.