Abstract: In order to obtain strains with the effect of preventing and controlling root-knot nematodes, the chitin flat transparent ring primary screening and the in vitro antagonistic test rescreening methods were used to obtain a fungal strain SFC-3 with biocontrol potential. Through observation of morphological characteristics and analysis and identification of transcribed spacer sequences (ITS) in fungi, the strain SFC-3 was identified as Trichoderma asperellum and its chitinase activity was 2.07 U/mL. The root-knot nematode egg parasitic experiment and the second-instar larval lethality experiment showed that the strain SFC-3 had the highest parasitic rate of 78.86%, which was higher than SFC-1, SFC-22 and other 9 strains. At the 7th day, the relative inhibition rate of egg incubation of root-knot nematodes reached 96.51%, and the corrected mortality rate of second-instar larvae reached 93.37%. In this study, by screening anti-knot nematode strains and studying their biocontrol effects, it was confirmed that the strain SFC-3 had better anti-root knot nematode performance.

Key words: root-knot nematode, Trichoderma echinosporium, chitinase activity, germplasm resources, biological control