Abstract: Actinomycetes are important antibiotics producing microorganism.In this study,testing tube method and thin layer chromatography pretesting revealed that the nematicidalactive substance produced by Streptomyces venezuelae Snea253 contained carbohydrate and amino acid moieties.The effects of active substance from Snea253 and some known oligosaccharides on egg hatching and J2 of Meloidogyne incognita were investigated.The results showed that active substance from Snea253 had the highest relative suppression rate of 84.95% on M.incognita egg hatching.However,maltose and sucrose have no significant inhibitory effect;In addition,galactose,fructose and xylose significantly promoted egg hatching of M.Incognita. Lactose,glucose and sorbitol sugar also had a promoting effect of egg hatching of M.Incognita, which however was not significant compared with the control group.The corrected mortality rate of M.incognita juveniles J2 caused by active substance from Snea253 was 98.21%,having a significant difference from that of oligosaccharides and control groups.On the contrary,glucose,lactose and sucrose were promoters of J2’s survival.Hence,it was concluded that ologosaccharides had no toxicity to root knot nemtode,however,nematicidal metabolites of Snea253 had strong activity to M.incognita.

Key words: Actinomycetes Snea253, Meloidogyne incognita, fermentation metabolites, nematicidal-active substance；oligosaccharide