Nematicidal activities of methanolic leaf extracts of Azadirachta Indica A. Juss and Ricinus communis L. on the root-knot nematode (Meloidogyne species) of potato (Solanum tuberosum L.)

Abstract

The effects of methanolic leaf extracts of Azadirachta indica A. Juss. and Ricinus communis L. on root-knot nematode (RKN), Meloidogyne spp. infecting potato were investigated. In in vitro experiment, 88 juveniles of RKNs were exposed to different concentrations of the extracts (0.375 mg/ml, 0.75 mg/ml, 1.5 mg/ml and 3mg/ml) for 24, 48, 72 and 96 hours. Distilled water served as the control. The treatments were laid out in a completely randomized design (CRD) with four replicates. The nematodes were observed for mortality. Potato varieties Caruso and Yellow were used for the pot experiment. The potatoes were inoculated with 1,000 juveniles of RKN at 2WAP. The treatments included three concentrations each (0.75 mg/ml, 1.5 mg/ml and 3 mg/ml) of Neem and Castor; Furadan (7.7 mg/ml); inoculated + un-amended and un-inoculated + un-amended. All treatments were replicated five times in a CRD. The in vitro experiment showed an increase in nematode mortality with increasing concentration and duration of exposure for all treatments. Neem caused higher nematode mortality than castor. Potato treated with Neem extracts had the best performance. Furadan was most effective in reducing galling in the potatoes. Variety Caruso performed better than variety Yellow. Alkaloids, carbohydrates and tannins were present in the extracts. Nematicidal activities of neem and castor leaves were established.