Toxicity and control efficacy of mixed parasitic fungal fermentation filtrates against soybean cyst nematode

Parasitic fungi is a kind of biocontrol resources with potential to control soybean cyst nematode(SCN).Fusarium spp., Verticillium chlamydosporium and Paecilomyces lilacinus have been widely found in continuous soybean field.In order to study the inhibition and control effects of these parasitic fungi on SCN, laboratory and greenhouse experiments were conducted.The fermentation filtrates were prepared from 12 strains of the 3 genera parasitic fungi isolated from SCN inhibition soil.The inhibition of the fermentation filtrates on cyst and egg hatching of SCN and the lethal effect on the 2nd instar larvae(J2) were determined under laboratory conditions.Four fermentation filtrates combinations with higher inhibitory effect were screened in greenhouse pot experiment.The results showed that the mixed parasitic fungal fermentation filtrates of 16 groups had strong inhibitory effect on cyst and egg hatching of SCN.The cyst hatching inhibition rate ranged from 59.1% to 87.8%, while the egg hatching inhibition rate ranged from 72.1 to 84.7.The lethal effect on J2 of SCN was more than 94% at 48 h, and it reached 100% at 72 h.Combination of F-V+P-V+V-21, F-V+P-E+V-25, F-9+P-V+V-25 and F-9+P-E+V-21 would significantly reduce the number of cyst, female, egg and J2 of SCN in root, and promote the growth of soybean.