LARVICIDAL AND ENZYME INHIBITORY EFFECTS OF ACALYPHA FRUTICOSA (F.) AND CATHARANTHUS ROSEUS L (G) DON. LEAF EXTRACTS AGAINST CULEX QUINQUEFASCIATUS (SAY.) (DIPTERA: CULICIDAE)

ABSTRACTObjective: The prime objective of this study is to evaluate the larvicidal and enzyme inhibitory effects of Acalypha fruticosa and Catharanthus roseusleaf extracts against Culex quinquefasciatus.Methods: Insecticidal susceptibility tests were carried out using the World Health Organization standard method, and the mortality was observedafter 24 hrs exposure.Results: The tested extracts showed a significant larvicidal activity depending on the dose of the plant extracts. However, maximum larval mortalitywas detected in ethyl acetate extract of A. fruticosa with a lethal concentration (LC50) value of 253.08 ppm and (LC90) value of 455.40 ppm followedby hexane extract of C. roseus with LC50 value of 645.33 ppm and LC90 value of 1452.88 ppm against the larvae of C. quinquefasciatus. In control, therewere five different fractions of α-carboxylesterases resolved in the gel with the mobilities ranging between 0.14 and 0.66. β-carboxylesterase isozymeprofile of larvae treated with hexane extract of A. fruticosa showed higher enzyme activities by way of intense staining of fractions both at 1/4 and1/10 LC50 value of 48 hrs treatments. A. fruticosa ethyl acetate extract, and C. roseus hexane extract exposed larvae indicated increased quantitiesof β-Est4/5 isozymes in the concentration of 1/4 and 1/10 of LC50 value of 24 hrs treatment when compared to control. The protein quantity in themajority of treatments decreased compared to control.Conclusion: The results revealed that the organic leaf extract of A. fruticosa and C. roseus had significant larvicidal and enzyme inhibitory effectsagainst C. quinquefasciatus.Keywords: Acalypha fruticosa, Catharanthus roseus leaves extract, β-carboxylesterase, Culex quinquefasciatus, Lethal concentration50

Antifeedant Activity of Crude Extracts and Fractions Isolated from Cymodocea serrulate (R.Br.) Leaf against Tobacco Caterpillar Spodoptera litura (Fab.) Lepidoptera: Noctuidae

Different organic solvent extracts of Cymodocea serrulata leaves exhibited antifeedant activity against Spodoptera litura larvae. Maximum antifeedant activity (88.95%) was observed in ethyl acetate extract at a 5 percent concentration. Five fractions were isolated from ethyl acetate extract by column chromatography and tested individually at four different concentrations, viz., 125, 250, 500, and 1000 ppm, for antifeedant activity. Among the five fractions, fraction I showed promising antifeedant activity (91.12%) at a 1000 ppm concentration. Deformities in larvae, pupae, and adults were also recorded.  The preliminary phytochemical analysis showed the presence of alkaloids, terpenoids, flavonoids, tannins, phenolic compounds, glycosides, and steroids

Assessment of the Phytotoxicity and Antifeedant Properties of Aristolochia bracteolata Lamk. Leaf Extracts and their Derivatives against the Spotted Bollworm, [Eariasvittella (Fab.)], (Lepidoptera: Noctuidae)

The phytopesticidal effects of various solvent crude extracts and isolated fractions from the leaves of Aristolochia bracteolata, which were tested for their antifeedant and larvicidal activities on the fourth instar larvae of the shoot and fruit of Earias vittella.The antifeedant and larvicidal activities were performed by fruit disc no-choice methods at 0.625, 1.25, 2.5, and 5% and 125, 250, 500, and 1,000 ppm concentrations for crude and fractions, respectively. The dichloromethane (DCM) extract of A. bracteolata exhibited the maximum antifeedant (61.10%) and larvicidal (65.33%) activities at 5% concentration against E. vittella, followed by hexane (44.93%), acetone (40.40%) and aqueous (22.25%) extracts. It was subjected to fractionation using silica gel column chromatography with different combinations of hexane and ethyl acetate used as the mobile phase. Among the six fractions obtained, fraction 6 showed the maximum antifeedant (78.32%) and larvicidal (81.77%) activities against E. vittella at a 1000 ppm concentration. The preliminary phytochemical analysis of the plant also showed alkaloids, anthroquinones, diterpenoids, flavonoids, glycosides, polyphenols, saponins, steroids, and tannins in the extract. A. bracteolata leaves could be complemented with an eco-friendly pesticide/insecticide for an integrated pest management strategy