光肩星天牛刻槽中一种细菌及其对天牛幼虫的致病性

Pathogenicity of Serratia marcescens Isolated from the Egg Niche of Anoplophora glabripennis

在分离光肩星天牛刻槽微生物时筛选出一种红色杆状细菌,经常规方法鉴定为粘质沙雷氏菌（Serratia marcescens）。室内试验显示该菌对天牛低龄幼虫有致死作用。用5个浓度梯度（7.8×10^10 - 2.0×10^7）接种低龄幼虫,结果显示,最高浓度剂量下幼虫死亡率可达80.6%,最低剂量下也有16.1%的死亡率。毒力回归方程为Y=0.6116x-0.6441,LD50=1.69×10^9个/ml。在野外试验中,将菌液喷于木段表面并将天牛成虫置于罩网木段上,使其产卵于木段,结果显示有皮下幼虫感染该菌致死,但防治效果仅有5.3%。

A bacteria isolated from the egg niche of Anoplophora glabripennis, identified as Serratia marcescens by normal methods, was lethal to early instars of the boring pest. Inoculation of five concentrations （from 7.8×10^10 to 2.0× 10^7） of the bacterial suspension to young larvae shows that mortality was 80.6% under the highest concentration and 16.1% under the lowest concentration. The toxicity regression equation was ： Y = 0.6116x - 0.6441, LD50 = 1.69 × 10^9/ml. In field experiment, wood trunks were sprayed with bacterial suspension and adult pairs were confined to the trunk in wire netting for oviposition. Mortality of the larvae was investigated two months later and found to be only 5.3 %.