The virulence of 3 parasitic fungi fermentation filtrates on race 4 of soybean cyst nematode

Fusarium spp.,Verticillium chlamydosporium and Paecilomyces lilacinus have been widely observed in continuous soybean field.In this study,we isolated 3 fungi from soybean field,and tested the inhibition of their fermentation filtrates on cyst and egg hatching to race 4 of soybean cyst nematodes (SCN) as well as mortality of the second instar larvae (J2) under laboratory conditions.The results showed that the fermentation filtrates of 12 strains from the 3 fungi had inhibitory effects on race 4 of SCN.The fermentation filtrates inhibited cyst and egg hatching of SCN,and had a lethal effect on J2.The inhibition rates of the fermentation filtrates from 12 strains on cyst hatching and egg hatching of SCN ranged from 50.6%-85.6% and 51.3%-69.7% respectively.The 5-fold,10-fold,20-fold and 50-fold diluents of the fermentation filtrates also showed an inhibitory effect on cyst and egg hatching of SCN.The fermentation filtrates from 12 strains had a lethal effect on J2 of SCN.The raw fermentation filtrates had lethal toxicity when J2 was treated 1 h later,and the lethal effect reached a peak from 48 to 72 h.Among the tested strains,the fermentation filtrates from F-9 strain of Fusarium,P-E strain of Paecilomyceslilacinus,and V-25 strain of Verticillium significantly inhibited soybean cyst nematodes.The results would provide information for the development of biocontrol bacteria against SCN.