Screening of highly virulent strains of fungi entomopathogenic to Scolytus schevyrewi Semenov
Author of the article:FAN Li-Hua1** NIU Hui-Lin2 ZHANG Jin-Tong1*** LIU Jin-Long1 YANG Mei-Hong1ZONG Shi-Xiang3
Author's Workplace：1. Institute of Chemical Ecology of Art and Science College, Shanxi Agriculture University, Taigu 030801, China;2. Gaoshawo Management Station of Ningxia Habahu Natural Reserve, Yanchi 751501, China;3. Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China
Key Words：Scolytus schevyrewi, pathogenicity, culture characteristics, chitinase, proteinase, FDA hydrolase activities, screening
Abstract： [Objectives] To identify highly virulent strains of fungi entomopathogenic to Scolytus schevyrewi Semenov, one of the boring pests of Ulmus pumila. [Methods] The pathogenicity of two superior strains, Bb773 and Pc546, to S. schevyrewi larvae was examined and the culture characteristics of these strains, including the final colony size, spore generation, sporulation and average growth rate, determined. A preliminary screening examined chitinase, proteinase and FDA hydrolase activities of the two selected strains. [Results] Adjusted death rates and median lethal time (LT50) of S. schevyrewi larvae ten days after infection with strains Bb773 and Pc546 at a concentration of 1×107 conidia/mL were 96.67%, 90.00％ and 3.61 d , 4.18 d, respectively. Chitinase, proteinase and FDA hydrolase activity of strain Bb773 was higher than that of strain Pc546 after about 2-10 days culture and proteinase activity was also significantly higher (P<0.05). [Conclusion] Strain Bb773 has greater potential as a biological control agent for the sustainable control of S. schevyrewi．