两株球孢白僵菌对核桃举肢蛾幼虫的感染试验

Infestation Experiment of Atrijuglans hetaohei Yang Larvae with the Two Strains of Beauveria bassiana

核桃举肢蛾的发生影响着核桃的产量和品质。为了寻找新的生物防治途径,于2014年8月从山西盂县核桃产区收集受核桃举肢蛾钻蛀的虫果进行解剖观察,发现在核桃举肢蛾钻蛀的初期、中期、后期和末期,核桃果实受害症状呈现不同的特点,包括果皮黑斑、果实内幼虫蛀食果肉形成的坑道和蛀孔的大小、排泄的虫粪量、幼虫的体色和体长。在虫果内核桃举肢蛾的幼虫数量平均为6~7头,最多的可达13头。利用球孢白僵菌的2个菌株TST05和FDB01的孢子悬浮液（孢子浓度为1.0×10^8个/m L）对新脱果的核桃举肢蛾老熟幼虫进行了感染试验。结果显示,2菌株对该幼虫均具有很好的感染和致病效果,感染第2天就表现出染病症状,随后虫体表面出现菌丝,最后完全被菌丝覆盖;第8天的校正死亡率分别为87.8%和84.4%;致死中时分别为4.743,4.934 d。

The infestation and damage of the pest Atrijuglans hetaohei Yang greatly reduced the yield and quality of walnut. To develop a new way for the pest biological control, the walnut fruits with larvae of Atrijuglans hetaohei were collected from Yuxian county in Shanxi province and were dissected and observed. The investigation showed that as the larvae boring the walnut fruits in early,medium, later, and final stage, different symptoms exhibited on the damage walnut fruits, including the black spots of walnut pericarp, the size of galleries and holes caused by larvae boring, quantity of faeces, color and length of larvae. The average number of the larvae inside of the infested walnut fruits was 6-7, but the most number could reach to 13 in one walnut fruit. Two strains of Beauveria bassiana TST05 and FDB01（sporeconcentration was 1.0×108/m L）were used to infect the mature Atrijuglans hetaohei larvae. The result showed that the two strains were very good in infection and pathogenicity to the larvae. On the second day after infection, the larvae showed the diseased symptom, later mycelia appeared on the surface of the larvae, at last the dead larvae was completely covered with a thick of mycelia. On the eighth day, the mortality rate reached 87.8% and 84.4% in the two strains infection, respectively, while the LT50 of the two strains were4.743, 4.934 d, respectively.