Nematicidal activity of Streptomyces aquilus JXGZ01 against the root-knot nematode Meloidogyne incognita

In this study, we evaluated the biocontrol effect against Meloidogyne incognita of Streptomyces (strain JXGZ01) obtained from yam field soil. Results showed that the mortality of second-stage juveniles (J2s) treated with an undiluted culture filtrate of JXGZ01 for 12 and 24 h was 70.86% and 85.58%, respectively. The twofold dilution resulted in 66.41% and 81.55% mortality for 12 and 24 h, respectively. Both strong acids and alkali significantly reduced the nematicidal activity of the culture filtrate, but neither temperature nor ultraviolet irradiation had any significant effect. In addition, two, four and eightfold dilutions inhibited the hatching of M. incognita eggs by 91.3%, 83.7% and 75.7%, respectively. Finally, the results of a pot experiment showed that the nematodes treated with different dilutions of culture filtrate significantly reduced the number of galls by 65.87%–97.30%. Compared with those of the control group, the treatments reduced the number of egg masses and J2s by 38.17%–92.84% and 37.57%–93.82%, respectively, and the eggs hatching rate was reduced by 27.92%–45.27%, relative to the control group. Data indicate that strain JXGZ01 has a potential and application value for development as a biocontrol agent for M. incognita.