Effects Of Different Sugar Sources On Proliferations And Pest Control Of Harmonia Axyridis

Sugar source substances are the main components of nectar,extrafloral and honeybew,which have a significant impact on the behavioral response,proliferation and pest control of natural enemy insects.Artificial sugar sources were used to replace sugar in nectar,extrafloral and honeybew,and their effects on behavior reaction,proliferation and pest control of Harmonia axyridis were studied.Some nectar plants that can replace sugar sources were screened to determine whether they can help to improve the proliferation and pest control effect of Harmonia axyridis,and provide reference basis for further utilization of Harmonia axyridis.(1)Sugar source has a significant effect on the proliferation and pest control of Harmonia axyridis.The selective tropism of Harmonia axyridis to sucrose,fructose,honey and glucose from different artificial sugar sources was deter mined by "Y" olfactometer.The results showed that the selective tropism of Harmonia axyridis to different sugar sources is significantly different from the control(P<0.001),Supplementing sucrose and fructose can significantly improve the survival rate of Harmonia axyridis larvae and increase the weight of 4th in star larvae and emerging adults,The highest survival rate of Harmonia axyridis larvae treated with sucrose was 94.03%,and the maximum body weight of4 th instar larvae and emerging adults is 0.0314 g and 0.0224 is treated with sucrose.Compared with the blank control,the survival time of the 1st instar larvae and the emergence adults of Harmonia axyridis fed only with honey,sucrose and glucose was significantly prolonged,Supplementing honey and sucrose in larval stage significantly prolonged the hunger tolerance time of adults.Harmonia axyridis fed only Drosophildae larvae does not lay eggs,Supplementing artificial sugar source can promote Harmonia axyridis to lay eggs,The maximum egg production of sucrose supplementation was 91.55 eggs.(2)The amount of Harmonia axyridis adults preying on Drosophildae larvae increased significantly after 8 days of supplementation with different artificial sugar sources,The total predation amount of Harmonia axyridis adults treated with sucrose for 8 days was 0.0734 g,which was significantly different from that treated with honey,fructose,glucose and clear water(P<0.05).The amount of predation on Drosophildae larvae by 4th instar larvae and newly emerged adults of Harmonia axyridis treated with sucrose in larval stage was significantly higher than that treated with honey,fructose,glucose and clear water in larval stage(P<0.05),The predation amount of 4th instar larvae and newly emer ged adults of Harmonia axyridis fed with sucrose in larval stage was 0.0132 g and 0.0147 g,respectively.(3)The attraction of nectar plants to Harmonia axyridis was measured by Y-shaped olfactometer.The results showed that the attraction of Salvia splendens,Tagetes erecta L,Hydrangea macrophylla(Thunb.)Ser and Ageratum conyzoides L to Harmonia axyridis was significantly different from the control group(P<0.001),and the attraction of Chinese rose to Harmonia axyridis was significantly different from the control group(P<0.05).(4)Nectar plants have a significant effect on the proliferation and control of Harmonia axyridis.The survival rate of Harmonia axyridis larvae treated with marigold was 90.62%,which was significantly higher than that of the control(P<0.05).The longest starvation resistance time of Harmonia axyridis adults only fed with Ageratum conyzoides L was 6.567 d days,which was significantly different from the control(P<0.05).Hydrangea macrophylla(Thunb.)Ser has the best effect on Harmonia axyridis preying on Lygus lucorum.