Suppression of Meloidogyne incognita and Meloidogyne hapla with entomopathogenic nematodes on greenhouse peanuts and tomatoes

We measured the effect of entomopathogenic nematodes on root-knot nematodes (Meloidogyne spp.) infecting tomato and peanut. In growth chamber experiments, peanut seedlings were inoculated with 300 Meloidogyne hapla eggs and 25 infective juveniles (IJs)/cm2 of Steinernema feltiae, Steinernema riobrave, or Heterorhabditis bacteriophora. With the exception of seedling roots treated with H. bacteriophora, M. hapla inside roots and egg recovery from seedlings treated with entomopathogenic nematodes were significantly less than those in the controls. Peanut plants in the greenhouse were infested with 5000 M. hapla eggs and treated 2 weeks before, 1 week before, at the same time, 1 week after, or 2 weeks after with 25 or 125 IJs/cm2 of S. feltiae, S. riobrave, or H. bacteriophora. Pre- and post-infestation applications of S. feltiae suppressed M. hapla penetration but not egg production. Only pre-infestation applications of S. riobrave suppressed M. hapla. Only the high application rate of H. bacteriophora applied at the time of M. hapla infestation was suppressive. Tomato plants in the greenhouse were infested with 5000 Meloidogyne incognita eggs and treated with 25 or 125 IJs/cm2 of Steinernema glaseri or Heterorhabditis megidis applied at the same times as the tomato treatments. The low rate of S. glaseri suppressed M. incognita penetration into tomato roots and the high rate of S. glaseri reduced egg production.