化学农药对茶小绿叶蝉成虫的防效及其原因探究

Study on the Control Effect of Chemical Pesticides on the Empoasca onukii Adults

茶小绿叶蝉(Empoasca onukii Matsuda)是茶园重要害虫,目前主要以化学防治为主,但化学农药对成虫的防治效果尚不明确。通过田间试验,评估了化学农药对茶小绿叶蝉成虫的防效;并通过室内模拟试验,探究成虫防效不佳的原因。结果显示,田间对若虫防效很好的化学农药对成虫的防治效果不理想。室内研究显示,以田间施药浓度甚至更低的浓度喷施整株茶梢时,成虫死亡率均为100%。当茶梢中部着药时,成虫死亡率最高,为63.33%~71.67%;但茶梢顶部着药时,成虫死亡率仅为20.00%~28.33%。当茶梢顶部着药时,通过增加茶梢周围的遮光范围或降低茶梢顶部的光照强度,可增加成虫的死亡率。这些结果表明,茶小绿叶蝉成虫活动范围主要在茶梢中部应是化学农药不能在田间对其有效控制的主要原因,且成虫这一习性与光强有着一定的关系。这一发现为田间茶小绿叶蝉成虫的防治提供了借鉴,有助于进一步提高化学农药对茶小绿叶蝉的防治效果。

Empoasca onukii is an important pest in tea gardens.Currently,the control was mainly depended on chemical pesticides,but less attention was paid to the control effect on the adults.In this study,the control effects of chemical pesticides on the adult E.onukii were evaluated through field experiments,and the reasons for the poor control efficiency were investigated by laboratory test.The results show that the chemical pesticides with good control effects on nymphs in the field did not have ideal control effects on adults.Indoor studies have shown that when spraying the entire tea shoots at concentrations even lower than those in the field,the adult mortality rates were 100%.Furthermore,the adult mortality rates were the highest(63.33%~71.67%)when the pesticides were applied at the middle part of tea plant shoots,and the adult mortality rates were the lowest(20.00%~28.33%)when applied at the top of shoots.Moreover,the adult mortality rate could be increased by increasing the shading range around the shoots or reducing the light intensity at the top of the shoots,when the pesticides were applied at the top of shoots.These results indicate that the main reason for the poor control efficiencies of chemical pesticides on the adult E.onukii in field is that the adults mainly live in the middle part of tea plant shoots.This phenomenon should also be related with light intensity.This finding provided a reference for the control of the adult E.onukii,and helped to enhance the control effects of chemical pesticides on E.onukii.