Utilizing endophytic plant growth-promoting bacteria and the nematophagous fungus Purpureocillium lilacinum as biocontrol agents against the root-knot nematode (Meloidogyne incognita) on tomato plants

Abstract The present investigation was designed to assess how administering biocontrol agents (BCAs) made from the nematophagous endophytic fungus MR20 ( Purpureocillium lilacinum ) or a mixture of endophytic plant growth-promoting bacteria MR12 ( Pseudomonas fluorescens ), and MR25 ( Serratia marcescens ), could enhance tomato growth and resistance to Meloidogyne incognita under in vivo conditions. The three strains’ cell-free culture filtrates showed a strong nematocidal impact ( P 4 mm, 2–4 mm, and < 2 mm) was more effectively achieved by treatment with P. fluorescens and S. marcescens than by treatment with P. lilacinum . Under in vivo conditions, the tested P. lilacinum or a mixture of P. fluorescens and S. marcescens effectively controlled nematode population densities below the economic threshold.