Suppression of Different Fungus Strains in Suppressive Soil on Heterodera glycines

Fungi could reduce nematode population by their antagonistic behavior and showed a great potential as biocontrol agents.The strains Dq012,Dq059,Dq003,Dq030 and Dq101 were isolated from nematode-suppressive soil by dilution.The effects of different strains on egg hatching and activity of second stage juvenile(J2) of Heterodera glycines were tested.The results showed that the corrected mortality rate of J2 was 80.84% when treated by Dq012,and about 70% by the other strains.The suppressive percentages of cyst hatching by Dq012,Dq059,Dq003,Dq030 and Dq101 were 87.69%,76.54%,87.31%,82.69% and 73.58%,respectively.The strains could disturb cyst formation on the surface of soybean root in the field.The suppression actions of Dq059 and Dq030 were the strongest and the weakest,respectively,with inhibition rates of 83.05% and 41.52%.The inhibition rate of Dq012 on cyst formation was 80.58%.In conclusion,the strain Dq012 had the highest inhibitory activity against Heterodera glycines,while the other four were similar,except that Dq030 was less effective in disturbing cyst formation.