杨毒蛾在西藏林芝的生物学特性

Study on Biological Characteristics of Stilphotia candida,in Nyingchi,Tibet

杨毒蛾作为近年来传入西藏的入侵物种,危害当地杨柳树的生长,通过对该害虫的生物学特性进行系统性研究,为该地区防治杨毒蛾及后续深入研究打下理论基础。通过野外调查、定期观察结合室内饲养的方法,从2021年4月到2022年7月,在林芝市结麦村设野外定点定期观察基地,同时采样进行室内饲养,对杨毒蛾在西藏林芝地区各虫态的形态特征、生活习性及年生活史等生物学特性进行了系统性的研究。结果表明:杨毒蛾在西藏林芝地区一年发生一代,以2—3龄幼虫9月中旬开始陆续越冬,越冬场所主要在杨柳树枝干树皮缝内侧或地表枯枝落叶层中,越冬幼虫于翌年4月中下旬开始危害杨、柳树新展叶片;在饲养过程中发现寄主挥发物是杨毒蛾卵正常孵化的必要条件之一,没有寄主挥发物的刺激卵可正常发育但幼虫无法孵化;通过杨柳树叶区分饲养发现北京杨叶饲喂下的幼虫其幼虫期明显短于白柳叶饲喂下的幼虫期,且幼虫成活率更高。杨毒蛾成虫多在夜间羽化,次日凌晨活动交尾,交尾时间长达11—17 h。自然变温条件下测得卵期、幼虫期、蛹期、雄/雌成虫期分别为20.17±2.34 d、44.03±4.00 d、9.67±1.81 d、5.7±0.84/4.9±0.94 d.

Stilphotia candida Staudinger,as an invasive species introduced into Tibet in recent years,harms the growth of local willow trees.The biological characteristics of the insect pests were systematically studied,which laid a theoretical foundation for the prevention and control of Stilphotia candida Staudinger in this area and the further research.Through the methods of field investigation,regular observation and indoor breeding,from April 2021 to July 2022,a fixed field observation base was set up in Jiemai village,Nyingchi city,and samples were collected for indoor rearing.The morphological characteristics,living habits and annual life history of Stilphotia candida Staudinger in Nyingchi,Tibet were systematically studied.The results showed that Stilphotia candida Staudinger occurred once a year in nyingchi Tibet,and began to overwinter with 2-3 instar larvae in mid-September.The overwintering sites were mainly inside the bark seams of willow branches or in the ground litter layer,and the overwintering larvae began to harm the newly developed leaves of poplar and willow in the middle and late April of the following year.During the feeding process,it was found that host volatiles were one of the necessary conditions for the normal hatching of Stilphotia candida Staudinger eggs,and the eggs could develop normally without the stimulation of host volatiles,but the larvae could not be hatched.Through the separate feeding of willow leaves,it was found that the larval stage of Beijing poplar leaves was significantly shorter than that of white willow leaves,and the survival rate of larvae was higher.Most of the Stilphotia candida Staudinger adults emerged at night and mate in the early morning of the next day,and the mating time was as long as 11-17 hours.At natural temperature conditions,the measured egg stage,larval stage and pupal stage,male/female adult period were 20.17±2.34 d,44.03±4.00 d,9.67±1.81 d and 5.7±0.84/4.9±0.94 d,respectively.