Management of Meloidogyne incognita on medicinal coleus by commercial biocontrol formulations

Abstract

The effects of commercial formulations of the plant growth promoting rhizobacterium Pseudomonas fluorescens, the antagonistic fungus Trichoderma viride, the egg parasitic fungi Paecilomyces lilacinus and Verticillium lecanii, and arbuscular mycorrhizal fungus Glomus mosseae, on root-knot nematode, Meloidogyne incognita, infecting medicinal coleus, Coleus forskohlii, were assessed under glass-house and field conditions and compared with that of the nematicide carbofuran. Dipping of stem cuttings in 0.1% P. fluorescens before planting gave the greatest reduction of M. incognita population density in soil, suppression of root-gall development and production of heavier root tubers of medicinal coleus. The root colonization of P. fluorescens was higher (38-110 × 104 colony forming units/g root) in softwood cutting dip treatment than in soil application. The next best treatment was soil application of P. lilacinus at 2.5 kg/ha, which parasitized the 51.5-71.5% of the nematode eggs. The effects of these treatments were comparable with that of the nematicide carbofuran. Application of V. lecanii as dip treatment of softwood cuttings was the least effective treatment.