Bioefficacy of hyptis suaveolens and melochia chorcorifolia against the armyworm, spodoptera litura (fab.) (lepidoptera: noctuidae)

The objective of the present study was to evaluate antifeedant, insecticidal, oviposition deterrent and ovicidal activity of different fractions obtained from the crude extracts of H. suaveolens (Lamiaceae) and M. corchorifolia (Sterculiaceae) against Spodoptera litura (Fab.) (Lepidoptera : Noctuidae), four fractions obtained from H. suaveolens, fraction III was found to inhibit the feeding ratio of the S. litura and it is apparent from the table. While in M. corchorifolia only three fractions have been obtained, among them fraction II was found to induced more feeding deterrent activity at 2000 ppm concentration. Ethylacetate extract of H. suaveolens yielded four fractions and diethylether extract of M. corchorifolia yielded five fractions. As per the data fraction III showed statistically significant ovicidal activity. It is also interesting to note that the same fraction was exerted strong ovipositional deterrent activity. Whereas, ethylacetate extract of M. corchorifolia yielded five fractions of which, fraction III showed increased ovicidal activity over the other fractions at higher concentration. Larvicidal activity obtained from the fraction II was significant than the other two fractions of the same extract. The larvicidal activity exhibited by the five fractions of diethyl ether extract of M. corchorifolia is shown in table 5. It is clear that fraction III at 1000 and 2000-ppm concentration was found to have increased activity than the other fractions.