Plant growth promotion and biological control of root-knot nematodes by Purpureocillium lilacinum isolated from a weed

Root-knot nematodes (Meloidogyne spp.) are significant agricultural pests, causing severe losses in many crops. Chemical nematicides remain the primary control method, but their environmental impact and costs call for alternative management strategies. Purpureocillium lilacinum, an entomopathogenic fungus, has demonstrated biological control potential against nematodes and other pests. In this study, strain S3, an endophytic fungus isolated from a grass weed, was evaluated for its plant growth-promoting effects and nematode suppression capabilities. In lettuce and cucumber, strain S3 significantly enhanced fresh weight and leaf development without inducing disease. Root-knot nematode density in the soil was reduced by approximately 69% following strain S3 inoculation, although reductions in root galls were not statistically significant. The observed nematicidal activity suggests that strain S3 functions similarly to P. lilacinum reported in previous studies. Given its potential as a biocontrol agent and plant growth promoter, endophytic fungus strain S3 may offer a sustainable approach to nematode management in crop production. Further research is needed to explore its application in antagonistic plants and optimize its efficacy in diverse agricultural systems.