桃园不同生境天敌对梨小食心虫卵致死效能的影响

The effect of natural enemies on the eggs of the oriental fruit moth Grapholita molesta,in four different types of peach orchard

【目的】为明确桃园不同生境中天敌对梨小食心虫(以下简称梨小)卵致死效能的影响。【方法】在自然混栽、清耕混栽、套种单植和清耕单植4种桃园中,定期悬挂梨小卵卡,周年动态监测梨小卵的被寄生率、被捕食率和自然死亡率。【结果】4-9月自然混栽、清耕混栽、套种单植和清耕单植果园梨小卵总死亡率分别为45.4%、25.3%、28.6%、34.6%;其中自然死亡率为12.0%、15.3%、14.7%、16.1%,各生境果园无显著差异(P>0.05);桃果生长期4种果园梨小卵的被寄生率分别为8.0%、1.1%、1.5%、2.7%,被捕食率分别为18.6%、4.6%、6.3%、2.4%;自然混栽果园梨小卵被寄生率、被捕食率均显著高于其他3种果园。桃果采收期4种果园梨小卵的被寄生率分别为5.5%、6.9%、15.4%、26.8%,被捕食率分别为39.2%、10.6%、8.7%、14.1%;自然混栽果园梨小卵被捕食率显著高于其他3种果园。寄生梨小卵的寄生蜂种类为松毛虫赤眼蜂Trichogrammadendrolimi和暗黑赤眼蜂Trichogrammapintoi,所占比例分别为50.8%和49.2%。【结论】复杂的果园生境能有效提高梨小卵的被寄死亡率和被捕食率,松毛赤眼蜂和暗黑赤眼蜂是果园昆虫卵期优势寄生性天敌。

[Aim]To clarify how different types of peach orchard affect the parasitism and mortality of Grapholita molesta eggs,and determine whether there is higher egg mortality in those with more complex habitats.[Methods]The parasitism rate,predation rate and natural mortality rate of G.molesta eggs were systematically investigated in four different types of peach orchards(natural and mixed planting,clean tillage and mixed planting,relay cropping and single planting and clean tillage and single planting)between April and September.[Results]The average mortality rate of eggs in the four different orchards was 45.4%,25.3%,28.6%and 34.6%,respectively,and the natural mortality rate was 12.0%,15.3%,14.7%and 16.1%,respectively.There was no significant difference among the four orchards in either of these variables.During the peach growing season,the mean parasitism rate in the four orchards was 8.0%,1.1%,1.5%and 2.7%,respectively,and the average predation rate was 18.6%,4.6%,6.3%and 2.4%,respectively.The parasitism rate and predation rate in natural and mixed planted orchards were both significantly higher than those in the other three orchard types.During the harvest season,the average parasitism rate in the four types of orchard was 5.5%,6.9%,15.4%and 26.8%,respectively,and the average predation rate was 39.2%,10.6%,8.7%and 14.1%,respectively.The predation rate of eggs in natural and mixed-planted orchards was significantly higher than in the other three orchards types.The percentage of eggs parasitized by Trichogramma dendrolimi and Trichogramma pintoi was 50.8%and 49.2%,respectively.[Conclusion]Complex orchard habitats can effectively stabilize the parasitism rate and improve the predation rate of G.molesta eggs.T.dendrolimi and T.pintoi appear to be the dominant egg parasitoids of fruit-boring insects in peach orchards.