烟芽夜蛾囊泡病毒3h株对草地贪夜蛾幼虫的感染特性及对其生长发育的影响

为寻找有效防控外来入侵物种草地贪夜蛾Spodoptera frugiperda的技术,以烟芽夜蛾囊泡病毒3h株(Heliothis virescens ascovirus 3h,HvAV-3h)为研究对象,通过测定不同龄期草地贪夜蛾幼虫口服或针刺感染HvAV-3h后的死亡率、存活时间、取食量及体重,分析该毒株对草地贪夜蛾幼虫的感染特性及对其生长发育的影响。结果显示,草地贪夜蛾1、2龄幼虫口服HvAV-3h后的校正死亡率分别为9.22%和0,3～6龄幼虫针刺感染HvAV-3h后的校正死亡率则高达100.00%,感染HvAV-3h的幼虫均在幼虫期或蛹期死亡。3～5龄幼虫针刺感染HvAV-3h后的存活时间明显长于健康幼虫;3～6龄幼虫针刺感染HvAV-3h后其体重和取食量均受到不同程度的抑制作用,体重抑制率分别为67.79%、41.68%、16.31%和10.30%,总取食量抑制率分别为57.80%、33.90%、17.42%和41.82%;其中3龄幼虫针刺感染HvAV-3h后的体重和取食量被显著抑制,且蜕皮困难,最终在幼虫期死亡;部分4～6龄感染HvAV-3h幼虫能够完成化蛹,但是均无法羽化。表明HvAV-3h感染能够有效控制草地贪夜蛾幼虫,有望开发为草地贪夜蛾的生防制剂。

Infection characteristics of Heliothis virescens ascovirus 3h (HvAV-3h) in Spodoptera frugiperda larvae and its effects on host growth and development

In order to find an effective method for controlling the invasive alien species Spodoptera frugiperda, Heliothis virescens ascovirus 3h (HvAV-3h) was used to inoculate the larvae of different instars per os or by injection. The survival time, the mortality rate, food intake and body weight of the larvae after infection were recorded. Further, the infection characteristics of HvAV-3h in S. frugiperda larvae and its effects on host growth and development were analyzed. The results showed that the corrected mortality rates of the first to second instars inoculated per os were 9.22% and 0, respectively. The corrected morbidity rate of the third to sixth instars inoculated by injection was up to 100.00% with all the infected larvae dead during larval or pupal stages. The survival time of the third to fifth instars infected by HvAV-3h was significantly longer than that of the healthy larvae. The body weight and food intake of the third to sixth instars infected by injection were inhibited to varying degrees. The weight inhibition rates of the third to sixth instars were 67.79%, 41.68%, 16.31% and 10.30%, respectively, and the total food intake inhibition rates were 57.80%, 33.90%, 17.42% and 41.82%, respectively. The body weight and food intake of the third instars infected by injection were significantly inhibited and all the infected larvae died due to the difficultly in molting during the larval stage. Some infected larvae in the fourth to sixth instars could pupate, but could not complete eclosion. In conclusion, HvAV-3h can effectively control S. frugiperda larvae and has the potential to be developed as a biocontrol agent for controlling S. frugiperda.