小菜蛾感染绿僵菌后的病征及组织病理变化

The Symptom and Histopathological Changes of Plutella xylostella Infected by Metarhizium anisopliae

小菜蛾感染绿僵菌后 ,虫体颜色及外部形态会发生相应变化。组织切片观察表明 ,绿僵菌菌株LD65处理后 3 6h ,附着于小菜蛾体壁的孢子开始萌发入侵。 48h后 ,小菜蛾内表皮被分解 ,菌丝段进入血腔 ,并向侵入点附近的脂肪体入侵。 3d后感染幼虫死亡 ,各组织器官均受到侵染。随着绿僵菌继续在死虫体内增殖 ,各组织器官遭到不同程度破坏。 5d后 ,菌丝突破体表 ,在虫体外形成菌丝层。菌株LF68侵染过程与LD65相似 ,但侵染速度快于LD65。

There were some changes in color and morphology on the diamondback moth infected with Metarhizium anisopliae. Paraffin sections showed the conidia of M. anisopliae strain LD65 attached to the integument of diamondback moth and germ tubes partially penetrated through the cuticle 36h postinoculation. After 48h, the endocuticle were disintegrated, the germ tubes had passed through the epithelial layers into the body cavity and invaded the fat body nearby the point of penetration. By 3d, infected larvae were dead and most tissures and organs were infected and disintegrated with the mutiplication of the hyphal bodies. The hyphae emerged through the cuticle and formed hyphal layer on the surface of the dead insect 5d postinoculation. The invasion process by strain LF68 were similar to that by LD65, but the invasion speed was faster than the later.