In vitro Studies of the Effectiveness of Five Plants Extracts Compared to Carbofuran in Controlling the Root Knot Nematode <i>Meloidogyne incognita</i>

Abstract

The crude aqueous extracts of five plants, Cleome viscosa L. Hyptis suaveolens Poit, Crotalaria retusa L., Jatropha curcas L., and Jatropha gossypifolia l., and a synthetic nematicide Carbofuran were studied in-vitro for their efficacy in controlling the rootknot nematode, Meloidogyne incognita (Kofoid and White) Chitwood. The experimental design was a randomized complete block design. The extracts were applied at 0, 5, 10,
15 and 20% while carbofuran was applied at 0, 100, 1000, 10,000 and 100,000 ppm. Fifty (50) freshly extracted eggs as well as fifty (50() freshly hatched juveniles were used. Observations were made after one (1), six (6), twenty four (24), forty-eight (48) seventytwo (72) hours for juvenile mortality and one (1), three (3), five (5) and ten (10) days for
egg hatch. All the treatments were replicated five times. It was observed that no eggs hatched in the higher concentrations (20% and 100 mg/ml) respectively of the plant extracts and carbofuran. It was also observed that by 24 hours all the juveniles that were exposed to 1 mg/ml, 10 mg/ml and 100 mg/ml carbofuran concentrations as well as more than 50% (59 98%) of all the juveniles in the 15 and 20 percent concentrations of all the plant extracts had died. All the treatments applied were superior in their effects in inhibiting egg hatch and causing juvenile death as compared with the control (distilled water only). Efficacy of treatments improved with increase in their concentrations and time of exposure of the nematode to treatment.