Control of root-knot nematode (Meloidogyne javanica) on tomato with molasses and other organic amendments

Abstract

In two pot experiments in which molasses (10 g molasses/L water) was drenched regularly onto field soils infested with root-knot nematodes (Meloidogyne javanica), both root galling and nematode reproduction were reduced. Results of in vitro experiments suggested that this suppressiveness of molasses to nematodes was not an osmotic effect, but was probably due to antagonism of nematodes by microorganisms that utilise it as a substrate. In a field grown tomato crop, the suppressive effects of sawdust (150 m3/ha) plus urea (600 kg/ha), filter press (400 m3/ha), molasses (375 L/ha/week for 14 weeks), a velvet bean green manure crop and the nematicide fenamiphos (10 kg a.i./ha) were compared. Untreated plants were heavily galled but all organic treatments except the green manure crop reduced root galling and all except the green manure crop and molasses reduced root-knot nematode populations in soil. Sawdust-amended soil was almost free of galls and had the lowest populations of root-knot nematode.