异色瓢虫对甜菜夜蛾和草地贪夜蛾的捕食潜能

The predation potential of Harmonia axyridis on Spodoptera exigua and Spodoptera frugiperda

为明确异色瓢虫Harmonia axyridis对甜菜夜蛾Spodoptera exigua和草地贪夜蛾Spodoptera frugiperda的捕食潜能,本文在室内条件下研究了异色瓢虫对上述2种鳞翅目害虫2龄幼虫的捕食功能反应和搜寻效应;在网室条件下测定了异色瓢虫对2种害虫低龄幼虫的防控效果。室内研究结果表明,异色瓢虫雌雄成虫对这2种害虫2龄幼虫的捕食功能反应均属于HollingⅡ型圆盘方程,其中雌成虫对甜菜夜蛾和草地贪夜蛾2龄幼虫的瞬时攻击率(a)分别为1.120和0.987,控害效能(a/T_(h))分别为134.514头和154.408头,日最大捕食量(1/T_(h))分别为120.124头和156.437头;雄成虫对甜菜夜蛾和草地贪夜蛾2龄幼虫的瞬时攻击率(a)分别为1.071和0.830,控害效能(a/T_(h))分别为116.262头和124.568头,日最大捕食量(1/T_(h))分别为108.540头和150.039头。网室试验结果表明,2∶300、4∶300和8∶300的益害比下异色瓢虫均能有效控制甜菜夜蛾和草地贪夜蛾低龄幼虫的数量,释放后8 d防效分别在65%、80%和95%以上。综上所述,异色瓢虫具备对甜菜夜蛾和草地贪夜蛾低龄幼虫有效控害的潜力,试验结果可为利用异色瓢虫防控甜菜夜蛾和草地贪夜蛾提供理论依据。

This study aimed to clarify the predation potential of Harmonia axyridis on Spodoptera exigua and S.frugiperda by investigating the predation functional response and search efficiency of H.axyridis towards the second-instar larvae of these lepidopteran pests under indoor conditions.The control effect of H.axyridis on early-stage larvae of S.exigua and S.frugiperda was evaluated in a net house.The indoor study demonstrated that both male and female adults of H.axyridis exhibited a HollingⅡtype functional response towards the second-instar larvae of S.exigua and S.frugiperda.The instantaneous attack rate(a)of female adults on S.exigua and S.frugiperda larvae was 1.120 and 0.987,respectively,with control efficiencies(a/T_(h))of 134.514 and 154.408 individuals,and daily maximum predation rates(1/T_(h))of 120.124 and 156.437 individuals,respectively.The instantaneous attack rate(a)of male adults on S.exigua and S.frugiperda larvae was 1.071 and 0.830,respectively,with control efficiencies(a/T_(h))of 116.262 and 124.568 individuals,and daily maximum predation rates(1/T_(h))of 108.540 and 150.039 individuals,respectively.The net house experiment showed that under the ratios of 2∶300,4∶300,and 8∶300,H.axyridis effectively controlled the population of early-stage larvae of S.exigua and S.frugiperda,with control efficiencies above 65%,80%,and 95%respectively,after eight days of release.In conclusion,H.axyridis shows potential for effective control of early-stage larvae of S.exigua and S.frugiperda.These experimental results provide a theoretical basis for the utilization of H.axyridis in integrated pest management strategies for these pests.