Abstract: The ultrastructure and development of a microspori dian,isolated from the dead body of ori ental migratory locust (Locusta migratoria manilensis) in Hebei province was observed under light-and electron-microscope.The meront was spherical or ovocylindrical containing uni-, bi-,quadri-and multinucle ate forms.The hexa-,eith-nucleate meronts measured 6.9×7.9μm were peculiar to this strain.The ultra strructure of stages in the life cycle of the mictosporidia showed that merontsdeveloped in direct contact with the host cell cytoplasm and bi-,guadrinucleates meronts were arrangment two nuclei in a diplokary on.Sporonts were differentiated from meronts with the thickened plasmalemma and observed undergoing cytokinesis.Stratified electron-dense strands were depostied in the host cell cytoplasm and sporont plas malemma surface.Studies of pathogenicity showed that the mortality increased as the dosage rised1the third-instar was more sUsceptible than that of the fourth;the mortality of locusts reard together was higher than reard sep arately;the develoment time of infected locusta were delayed 2~ 3 days;the number of eggs infected lo custs decreased;the food consumption of the infected was 35~ 75%less than controlled after 24 days’ inoc ulation.

Key words: Nosema locustae, Locust, Ultrastructure

摘要： 从我国东亚飞蝗上分离出微孢子虫病原物圆形裂殖体(Meront),除单核、双核和四核外,还在本菌株观察到六核、八核等多核裂殖体。超微结构生活史观察,裂殖体细胞质膜很薄,与寄主细胞紧密相接,其细胞内含许多核糖体、囊泡和大量光滑内质网、双核、四核裂殖体,均呈双核相伴排列,以及正进行细胞质分裂的裂殖体和产孢体(Sporont);产孢体细胞壁加厚明显区别于裂殖体。整个生活史均为双核相伴排列。产孢体表面有多层电子致密物质呈短线条沉积。成熟孢子极膜层为指纹状片层结构,极丝圈18～20个。该病原物主要感染脂肪体和唾腺,并能引起寄生死亡,其死亡率有随接种剂量的增高而增大的趋势,而且3龄比4龄更敏感。接种后群体饲养比单头饲养死亡率高。病虫比健虫生育期延长2～3天,产卵能力下降,接种后24天病虫食物消耗比健虫减少35～75%。

关键词: 蝗虫微孢子虫, 蝗虫, 超微结构