益蝽对烟草斜纹夜蛾幼虫的捕食能力评价

Evaluation of Predation Ability of Picromerus lewisi to Spodoptera litura Larvae

为明确捕食性天敌昆虫益蝽捕食烟草斜纹夜蛾的能力,在温度(25±1)℃、相对湿度(65±5)%、光周期16L∶8D的室内条件下,开展了益蝽捕食烟草斜纹夜蛾幼虫的捕食功能反应试验。结果显示,益蝽对烟草斜纹夜蛾3、4、5龄幼虫的捕食功能反应均符合HollingⅡ方程;益蝽成虫对3、4、5龄斜纹夜蛾的日最大捕食量分别为59.20、27.36、9.68头;瞬时攻击率分别为1.077 3、1.070 5、1.529 6;处置时间分别为0.016 9、0.036 5、0.103 3 d;从反应捕食能力的a/Th值来看,益蝽捕食3、4、5龄幼虫的a/Th值分别为63.77、29.29、14.81,表明益蝽对3龄幼虫具有最强的捕食力。表明在利用益蝽进行生物防治时,当田间斜纹夜蛾幼虫达到3龄高峰时,释放益蝽可取得更好的防治效果。

In order to determine the predatory ability of the natural enemy Picromerus lewisi to Spodoptera litura larvae, the predatory ability of Picromerus lewisi to Spodoptera litura larvae was tested under the indoor conditions of temperature(25±1)℃,relative humidity(65±5)%,photoperiod(16 L∶8 D).The results showed that the predatory function response of the insect Picromerus lewisi to the tobacco Spodoptera litura 3,4,and 5 instars all accorded with the HollingII disc equation.The daily maximum predation of the adult of the Picromerus lewisi to the 3 rd, 4 th and 5 th instar Spodoptera litura was 59.20,27.36 and 9.68 respectively;the instantaneous attack rate was 1.077 3,1.070 5 and 1.529 6 respectively;the disposal time was 0.016 9,0.036 5 and 0.103 3 d respectively;from the point of view of the a/Th value that reflecting the strength of predation ability, a/Th values of the 3 rd, 4 th, and 5 th instar larvae of the Picromerus lewisi were 63.77,29.29 and 14.81,respectively, which indicated that the predation ability of the Picromerus lewisi to the third instar Spodoptera litura was the strongest.The results showed that when the Picromerus lewisi was used for biological control, when the field Spodoptera litura larva reached the third instar peak, the Picromerus lewisi could be released to achieve better control effects.