小菜蛾感染玫烟色棒束孢后的病征及组织病理变化  

The symptoms and histopathological changes of Plutella xylostella larvae infected with Isaria fumosorosea

作　　者：雷妍圆[1] 吕利华[2] 何余容[1] 韦秉兴[3] 

机构地区：[1]华南农业大学资源环境学院,广州510642 [2]广东省农业科学院植物保护研究所,广州510640 [3]广西大学农学院,南宁530005

出　　处：《植物保护学报》2011年第2期147-152,共6页Journal of Plant Protection

基　　金：公益性行业(农业)科研专项(200803001);广东省农业攻关项目(2006B20301037)

摘　　要：为了明确玫烟色棒束孢对小菜蛾的致病作用,分别以1×105孢子/mL和1×108孢子/mL浓度的玫烟色棒束孢菌株EBCL03011孢子悬浮液感染小菜蛾幼虫,观察了感病幼虫体表和体内器官组织的病变情况。结果显示,感病虫体颜色由局部浅褐色逐渐变为大面积深褐色,病虫出现缩短、强直等外部形态的变化。组织切片观察显示,接种后4 h,附着于体壁的分生孢子开始萌发入侵;16h后,小菜蛾内表皮被分解,菌丝段进入血腔。与此同时,被幼虫取食进入消化道的分生孢子也增殖产生菌丝段,以菌丝段突破肠壁细胞,向附近的脂肪体入侵;随着玫烟色棒束孢继续在虫体内增殖,24 h后各组织器官遭到不同程度破坏;48 h后,感病幼虫死亡,虫尸体内的菌丝突破体表,在虫体外形成菌丝层。表明玫烟色棒束孢入侵小菜蛾有两条途径,第1条为体表途径,第2条为消化道途径。In order to clarify the pathogenicity of Isaria fumosorosea（Paecilomyces fumosoroseus）（Hypocreales： Cordycipitaceae） to Plutella xylostella（Lepidoptera： Plutellidae）,The tissues and organs of P.xylostella larvae infected with an indigenous strain EBCL 03011 suspension of I.fumosorosea at two concentrations of 1×105 conidia/mL and 1×108 conidia/mL were investigated.The results showed that infected larvae cuticle gradually became dark brown,the whole body of the insect thickened and reduced in size.Paraffin sections of infected larvae organs observed under light microscope indicated that the conidia of I.fumosorosea attached with the integument of P.xylostella larvae penetrated through the cuticle by germ tubes after 4 h postinoculation.After 16 h,the endocuticle and gut wall cells were disintegrated,the germ tubes passed through the epithelial layers and gut cavity into the hemocoel,then invaded the muscle tissues and fat body nearby the area of penetration.After 24 h,most tissues and organs of infected larvae had different degrees of disintegration with the multiplication of the hyphal bodies.The hyphae emerged through the cuticle and formed a hyphal layer on the surface of the cadaver after 48 h postinoculation.Our results indicated that there were two different pathways of invasion after conidia of I.fumosorosea EBCL03011 inoculated to P.xylostella larvae.One was the cuticle way,the other was the digestive tract way.

关 键 词：小菜蛾 玫烟色棒束孢 外部症状 组织病理 

分 类 号：S476.1[农业科学—农业昆虫与害虫防治]