The control effect of concealed pesticide application on Aphis citricola and its effects on natural enemies
In order to clarify the control effects of pesticides on aphids in Beijing Yuyuantan park,a concealed pesticide application system was established,and the control effects of thiamethoxam and imidacloprid against Aphis citricola were compared by trunk hanging bottle injection method,the control effects of thiamethoxam on Aphis citricola using root application method and trunk hanging bottle injection method were compared.The effects of different treatment agents and concentrations on the population of natural enemies were observed,and the predatory dominant natural enemy population was clarified.The results showed that the maximum control effect of thiamethoxam 70%WG on Aphis citricola was 65.78%on the 7th day after application by trunk hanging bottle injection method.The maximum control effect of thiamethoxam 3%GR on Aphis citricola was 64.65%on the 21th day after application by root application.The investigation found that there were five natural enemies of Aphis citricola,and the dominant natural enemies were Harmonia axyridis,Chrysopa pallens,Syrphidae and Aphidius,accounting for 29.35%,27.98%,23.11%and 12.96%,respectively.The concealed application of thiamethoxam and imidacloprid was safe for predatory natural enemies.