Sustainable Management of Root Knot Nematode (Meloidogyne Spp) on Tomato : The Use of Castor Bean (Ricinus Communis)Aqueous Extracts

Apart from high cost, increased concern for environmental and health hazards has called for a reduction in the use of synthetic nematicides for nematode control.In vitro studies in Petri dishes showed that castor bean extracts had toxic effect on eggs and juveniles of root-knot nematodes. Egg hatch inhibition and juvenile mortality decrease with increased dilution of the extract. With an increase in exposure time, juvenile mortality increased.Trials were conducted to observe the effect of the extract on root-knot nematode and some growth parameters of tomato plant in pot. Seedlings either dipped, side-drenched or a combination of both with different concentrations of castor bean extracts showed that plant height, stem girth, fresh shoot and root weights of extract-treated plants were significantly different from those of the control plants. Numbers of root-knot juveniles and galls on the roots of the extract-treated plants were significantly different from those of the control. The crude castor bean extract was nematotoxic to root-knot nematodes in vitro and potted tomato.This study should help shed light on the use of botanicals in managing plant parasitic nematodes on vegetables.