Bioactivity of Melia azedarach L. was tested against diamondback moth (DBM), Plutella xylostella L. in the laboratory. The adult of DBM laid significantly lesser number (upto 71%) of eggs on the surfaces treated with methanolic extracts of M. azedarach than on those treated with solvent only. When larvae derived from above eggs were reared on fresh food, the mortality in the larval stage was upto 22.8% and that in pupal stage was upto 29.6%. The methanolic extracts also reduced feeding among the larvae significantly, when methanolic extract-treated food was offered to second instar larvae in a different set of experiment, thus, indicating an antifeedant effect.
