黄绿绿僵菌对褐飞虱侵染过程的扫描电镜观察

Observations on infection of Nilaparvata lugens by Metarhizium flavoviride using a scanning electron microscope

本实验利用扫描电镜观察了黄绿绿僵菌Metarhizium flavoviride菌株分生孢子对褐飞虱Nilaparvata lugens(Stl)的侵染过程。结果表明:分生孢子多分布在褐飞虱节间膜、体表的褶皱凹陷等部位,主要以芽管或产生附着胞入侵,然后在体表长出菌丝和产孢。菌体进入寄主血腔后,利用体腔内营养大量增殖、扩散并侵染褐飞虱卵巢中的卵块。侵染卵块的菌丝虽被体液包裹但依然能继续生长,使卵粒失活,抑制害虫下代的数量。通过体表及体内的侵染过程,可直观地表现黄绿绿僵菌对褐飞虱的侵染能力和侵入方式,为评价该菌的杀虫作用和应用前景提供了证据。

The process by which Metarhizium flavoviride conidia infect Nilaparvata lugens（Stl） was observed using a scanning electron microscope（SEM）.The results show that most conidia were deposited on the intersegmental membranes which are folded regions on cuticle.The germinated conidia of the isolate invaded the cuticle not only directly via germ tubes,but also by producing appressoria during the course of infection.After this hyphae and spores grew on cuticle.Thalluses entered into the hemocoel and then made use of nutrition to reproduce in large quantities,diffussing and infecting the insects＇ eggmass.Even though covered with humoral hyphae,the infected eggmass still continued to grow but ongoing fungal activity inactivated many eggs thereby reducing the number of insects produced in the next generation.Scanning electron microscopy allowed us to observe the infection process both in vitro and in vivo,thereby providing useful information for evaluating the insecticidal effect and utility of Metarhizium flavoviride as a control agent for N.lugens.