天蚕白僵病的菌种鉴定及致病性的研究

Identification of the Pattogen of While Mascardine Infesting Japanese 0ak Silkworm and Its Pathogenesity

天蚕患白僵病后使蚕体色稍暗、食欲减退、行动呆滞、蚕体上出现油渍状病斑,死前排软粪,尸体硬化,最后被白僵菌的白色菌丛所覆盖。引起天蚕白僵病的病原菌是[Beauveria bassiana(Bals.)Vuill.],分生孢子呈球形或卵圆形,球形直径2.5～4.4μm,卵圆形为2.8～4.4×2.5～3.8μm,多数分生孢子堆积在一起呈白粉状。体内的营养菌丝呈丝状无色,具隔膜,分枝生长,直径为2,5～3.3μm。芽生孢子圆筒形,大小为6.3～46.6×1.0～3.9μm。体表的气生菌丝直径为2.5～3.3μm,无色具隔膜,分枝生长。试验证明白僵菌能经接触侵染天蚕、桑蚕和柞蚕虫体引起白僵病,来自3种蛋体上的白僵菌可以互相感染,感染率均为100％。

The pathogen of white museardine infesting Japanese oak sickworm has been identified as Beauvaria bassiana. The infested worm is cheracterized by sluggish movement, slighly dark body color, poor appetite and the appearance of oil-stainirg spots on the body surface. Conidiorposes of Beauvaria bassiana are globular(5～4.4μm in diameter) or oval (2.3～4.4×2.5～3.8μm), a large number of which pile together like flour. The vegetative muycelium within the body and the aerial mycelium are filiform, colorless, septiferous, 2.5～3.3μm in diameter, and grow dichotomourly. The budding spores are cylindric, 6.3～46.6× 1.9～3.9μm in size. The white murcardine is spread by way of contact in fection, which may occur among the Japanese oak silkworm.chinese oak sillkworm and the domestic silkworm and the infestion sate reaches 100%.