Abstract: To further enhance the inhibitory effect of Streptomyces europaeiscabiei strain JXJA01 on second-instar larvae of Meloidogyne incognita (southern root-knot nematode), the corrected mortality rate of the strain against second-instar larvae of Meloidogyne incognita was used as the screening index. The optimal fermentation medium was first screened through single-factor experiments, and on this basis, response surface analysis was conducted to optimize and obtain the best fermentation medium formula and optimal fermentation conditions. The results showed that the optimal fermentation medium for this strain was fermentation medium D. Further optimization experiments on fermentation conditions revealed that when the fermentation medium contained 8.57 g/L soluble starch, 2.31 g/L urea, 0.34 g/L ammonium sulfate, 0.40 g/L calcium carbonate, and 0.40 g/L sodium chloride, with a fermentation temperature of 28 ℃, an inoculum size of 6%, an initial pH of 7.6, and a fermentation time of 5 days, the corrected mortality rate of the strain’s fermentation broth against second-instar larvae of Meloidogyne incognita reached 96.78% ± 1.89%, which was 22.73 percentage points higher than that before optimization.​

Key words: Streptomyces europaeiscabiei JXJA01, Meloidogyne incognita, optimization of fermentation conditions, biological control