【摘要】 本文研究了小地老虎、家蚕、直纹稻苞虫和二化螟幼虫对苏云金杆菌的患病症状及组织病变。经口摄入致死剂量细菌后,家蚕、直纹稻苞虫表现出强烈症状,4—8小时内血淋巴 pH 值上升,迅速瘫痪死亡;二化螟没有明显的外部症状,血淋巴 pH 值保持不变,2—3日死亡。小地老虎不感病,行为、血淋巴 pH 值、组织形态等均无异常表现。苏云金杆菌的三个株系对同一幼虫所引起的症状和组织病变基本相同。细菌伴孢晶体分解毒素导致幼虫中肠敏感部位细胞坏死、脱落是幼虫死亡的直接原因;中肠坏死后,细菌进入血腔引起败血症进一步破坏了虫体的其它组织、器官。更多还原

【Abstract】 The difference and characteristics of the symptomes and the histo-pathological changes of four species of lepidopterous larvae,the blackcut worm(Agrotisypsilon),the silk worm(Bombyx mori),the riceskipper(Parnara guttata)and the rice stem borer(Chilo suppreslias),caused by Bacillus thuringiensis were studied in 1984.While the lethaldose of bacteria were in jested,the ph values of hemolymph of thesilk worm and the rice skipper apperently increased in 4—8 hours,then larvae fell into paralysis and died eventually.For the rice stemborer,the hemolymph ph value was unchange,the larvae died frommidgut collapse.The results of histological observation revealed thatthe death of larvae was mainly due to the histopathological changesin the midgut caused by paraspore crystal toxin of the bacteria.Bythe collapse of the midgut,the bacteria entered the larva hemocoelom,causing septicaemia and destroying other organs and tissues.Thesymptomes and histopathological changes showed no difference in la-rvae of one species infected by each of the three strains of the bac-teria separately.更多还原