Bioefficacy of Crotalaria juncea L. extracts against rice root knot nematode, Meloidogyne graminicola*
In vitro toxicity (LC50) of methanol (M), ethyl acetate (EA) and hexane (H) extracts of Crotalaria juncea on Meloidogyne graminicola J2s indicated that methanol extract was 1.04 times more toxic to J2s of M. graminicola compared to hexane and ethyl acetate extracts. Moreover, the mortality of J2s increased with the increase in the concentration of all the three extracts of C. juncea. In the pot study, roots of seedlings were dipped into the solutions of Crotalaria extracts (M & H) @ 500, 250, 125, 62.5 μg/ml and carbofuran for about 20 min. In general, the plant growth parameters (shoot length, shoot weight, root length & root weight) of rice plants improved at 500 μg/ml concentration of M and H extracts. Shoot length at all the concentrations of extracts were found to be on par with carbofuran application. At 60 DAI, maximum shoot length 37.90 cm and 38.72 cm was observed at 500 μg/ml in methanol and hexane extracts, respectively compared to control (21.40 cm). Among the three extracts tested, methanol extract @ 500 μg/ml was highly effective against M. graminicola in both in-vitro and pot study.