Effects of yeast fermentation broths on the Meloidogyne incognita population in soybean

Root-knot nematodes are pathogenic to a wide range of plants worldwide and can reduce the yield potential of important crops. The objective of this study was to investigate the potential effects of yeast fermentation broths (YFBs) on the hatching of Meloidogyne incognita second-stage juveniles (J2s) in vitro. In addition, application methods of the yeasts for the control of the nematode in soybean were evaluated. Fermentation broths (FBs) of Pichia manshurica CCMA0762, Pichia caribbica CCMA0759, Lachancea thermotolerans CCMA0763, Hanseniaspora opuntiae CCMA0760 and Kodamaea (Pichia) ohmeri CCMA0758 were evaluated in the hatching test in vitro. The same treatments were separately applied to the soil, soil+shoot and shoots of plants inoculated with M. incognita, and the results were compared with those of the control and those from a yeast-based commercial product. L. thermotolerans CCMA0763 and P. caribbica CCMA0759 FBs were selected for evaluation of nematode infection. All YFBs inhibited J2 hatching. The L. thermotolerans FB reduced the number of nematodes in one experiment when applied to soil. The most effective application mode differed by FB type. L. thermotolerans and P. caribbica FBs, when applied to shoots, decreased the number of J2s, sausage-shaped juveniles, adult females and total nematodes at different evaluation times.