玫烟色虫草和球孢白僵菌对朱砂叶螨和二斑叶螨的致病力评价

为探寻具有杀螨潜力的生防真菌，采用喷雾法测定分析玫烟色虫草Cordyceps fumosorosea IF-1106菌株和球孢白僵菌Beauveria bassiana BB-1339菌株对朱砂叶螨Tetranychus cinnabarinus和二斑叶螨Tetranychus urticae卵、幼螨及雌成螨的致病力。结果表明，感染玫烟色虫草IF-1106菌株和球孢白僵菌BB-1339菌株后螨类的形态特征不一致，感染IF-1106菌株后形成棉絮状菌丝，而感染BB-1339菌株后则形成羊毛状菌丝。IF-1106菌株和BB-1339菌株对朱砂叶螨和二斑叶螨卵的LC₅₀分别为2.38×10⁷、8.26×10⁷CFU/mL和4.48×10⁷、1.21×10⁸CFU/mL，对朱砂叶螨和二斑叶螨幼螨的LC₅₀分别1.97×10⁷、8.26×10⁷CFU/mL和7.65×10⁶、8.99×10^5...

Pathogenicity of entomopathogenic fungi Cordyceps fumosorosea and Beauveria bassiana against mites Tetranychus cinnabarinus and Tetranychus urticae

In order to determine the biological control potential of Cordyceps fumosorosea and Beauveria bassiana, the pathogenicities of entomopathogenic fungus strains, IF-1106 and BB-1339 against eggs, young mites and female mites of Tetranychus cinnabarinus and T. urticae were investigated by using spray method in the laboratory. The results showed that the morphological characteristics of the mites were different between mites after infection by the IF-1106 and BB-1339. The cotton-like hyphae were formed after infection by IF-1106, while the wool-like hyphae were formed after infection by BB-1339. The lethal median concentrations (LC₅₀) of IF-1106 against T. cinnabarinus and T. urticae eggs were 2.38×10⁷ CFU/mL and 8.26×10⁷ CFU/mL, respectively, while the LC₅₀ values of BB-1339 against the eggs of the two mite species were 4.48×10⁷ CFU/mL and 1.21×10⁸ CFU/mL, respectively. The LC₅₀ values against young mites were 1.97×10⁷, 8.26×10⁷ CFU/mL and 7.65×10⁶, 8.99×10⁵ CFU/mL, respectively, while the LC₅₀ values against female adults were 9.68×10⁷, 8.02×10⁷ CFU/mL and 6.36×10⁷ and 2.95×10⁷ CFU/mL, respectively. The results indicated that C. fumosorosea was suitable for controlling mite eggs, while B. bassiana was more effective in controlling nymphs and adult mites, and also more pathogenic against young mites.