The screening of aphids killing fungus

摘要

Fifteen fungi of two genus, Paecilomyces and Beauveris, collected from different areas were studyed. The pathogenicities of them to the second- third old aphids (Brevicoryne brassicae) were tested with their spore suspensions (1×10~7 conidia/ml). the result showed, the cumulative mortalities of seven strong pathogenic strains were from 60.00% to 97.78% in 7 days. We also analyzed their velocity of growth, quantity of sporulation, germination rate of conidia and their contents of exopolysaccharide. At last, we discussed the relationship between these parameters and the lethal rates.