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朱砂叶螨Tetranychus cinnabarinus是多食性主要农业害螨,对化学杀螨(虫)剂抗药性极强,尤其缺乏有效的螨卵灭除剂.通过生物测定发现,球孢白僵菌Beuaveria bassiana SG8702菌株和玫烟色拟青霉Paecilomyces fumosoroseus Pfr153菌株能有效侵染该螨的卵,使其致死而不孵化,受染卵变形变瘪,在保湿条件下卵表长出菌物并产生大量分生孢子.在58,298和1306个孢子/mm2的接种剂量处理(每剂量重复3次,每重复35-65粒卵)下,SG8702在25℃和12L:12D条件下对螨卵的校正侵染致死率分别为(20.4±4.2)％,(36.0±7.6)％和(64.6±12.5)％,Pfr153在129,402和2328个孢子/mm2的接种剂量下分别致死螨卵(16.1±11.1)％,(44.2±13.3)％和(63.4±11.7)％,而两次生测对照处理中的螨卵自然死亡率分别仅为7.8％和10.3％.根据几率分析结果,SG8702和Pfr153对供试螨卵的LC50分别为548(393-858)和914(625-1550)个孢子/mm2,显示前者的杀卵效果优于后者.这是关于丝孢类昆虫病原真菌杀螨卵活性的首次发现和报道.
Tetranychus cinnabarinus, a major multi-herbivorous agricultural mite, is highly resistant to chemical acaricides (insects) and especially lacks an effective mite egg-killing agent.According to bioassay, Beauveria bassiana SG8702 strain And Paecilomyces fumosoroseus Pfr153 could effectively infect mite eggs to death without hatching, and the infected eggs degenerated and became deflated. On the condition of moisturizing, the eggs grew out of the strain and produced a large number of conidia . The lethality of the correctional infestation of mite eggs by SG8702 at 25 ° C and 12L: 12D at an inoculation dose of 58, 298 and 1306 spores / mm2 (3 replicates per dose, 35-65 eggs per replicate) Were (20.4 ± 4.2)%, (36.0 ± 7.6)% and (64.6 ± 12.5)%, respectively. Pfr153 caused 16.9 ± 11.1% of dead mite eggs at the doses of 129, 402 and 2328 spores / ) And (63.4 ± 11.7)%, respectively, while the natural mortality rates of mite eggs in the two treatments were only 7.8% and 10.3%, respectively.According to the odds analysis, the LC50 of SG8702 and Pfr153 on mite eggs were 548 (393-858) and 914 (625-1550) spores / mm2, indicating that the former is better than the latter in killing eggs. Trichosporon insect pathogenic fungi egg acaricidal activity was first discovered and reported.