Author(s):

M Ramanan and N Muthukumaran

Abstract: Studies were carried out to determine the effect of <em>Senna alata</em> L. solvent seed extracts on third instar <em>Spodoptera litura</em> Fab. using leaf disc bioassay method. Seven different concentrations (5, 10, 20, 30, 50, 70 and 90 %) along with solvent control and absolute control were tested. The extracts showed diverse anti insect properties such as feeding deterrence, insecticidal and insects growth regulatory activity at different concentrations. Among the different solvent extracts of seed, the acetone extract showed maximum feeding deterrence activity of 95.22 per cent in higher concentration. When concentration increased the feeding deterrence was also found to be increased. In other solvent extracts, feeding deterrence was &lt; 50 per cent. The maximum larval mortality (80%) was noticed in methanol extract. In ethyl acetate extract, maximum of 40 per cent larval malformation and 60 per cent pupal malformation were noticed. The experiment revealed that among various seed solvent extracts of <em>S.alata</em> tested against <em>S. litura</em>, the acetone extract of seed in higher concentration showed maximum feeding deterrence activity, the ethyl acetate extract of seed showed insect growth regulatory activity and methanol extract of seed showed insecticidal activity.

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