不同酯酶型球孢白僵菌株系及相同酯酶型株系经寄主转移后毒力变化的研究

对12个酯酶型的16株白僵菌进行了毒力生物测定.结果表明,不同酯酶型株系对松毛虫的毒力差异显著,LT50可相差数倍;同一酯酶型株系经不同寄主转移后,其毒力也发生了较明显的变化.如从松灰象甲上分离出的不同酯酶型的2株白僵菌MGS980404-21(酯酶型05),MGS980510-06(酯酶型06)]和人工释放的酯酶型02菌株Bb13毒力都很高,而从松灰象甲分离出的与释放菌株属同一酯酶型的另一个菌株MGS980507-34,毒力虽然很低,但却是林间最常见的流行菌株.上述结果理解为白僵菌在林间的宿存,尤其是它在松毛虫低虫口状态下能在林间长期宿存不绝的原因,以及对于从林间采集筛选高毒菌株提供了可能.

Virulence Change of Beauveria bassiana Strains with Different and the Same Esterase Types after Host Transfer

Virulence of 16 Beauveria bassiana strains belonging to 12 esterase types on the pine caterpillar was tested in a bioassay.The result showed that virulence of strains in different esterase types differed significantly with LT_(50) difference up to several times.The virulence of strains in the same esterase type also changed obviously after host transfer. The virulence of 2 strains, MGS980404-21 of esterase type 05 and MGS980510-06 of esterase type 06, and artificially released Bb13 of esterase type 02 were high,while the the virulence of another strain,MGS980507-34 of esterase type 02,isolated from the grey pine weevil,Brachyderes incanus was low, but it was a prevailing strain in the pine ecosystem.The above results provide evidence for understanding survival of B.bassiana in forest, especially long-term persistence when the pine caterpillar population was at very low level,as well as for sieving of virulent strains.