Kathirvelu Baskar

Antifeedant, larvicidal and pupicidal activities of Atalantia monophylla (L) Correa against Helicoverpa armigera Hubner (Lepidoptera: Noctuidae).

Antifeedant, larvicidal and pupicidal activities of hexane, chloroform and ethyl acetate extracts of Atlantia monophylla leaf were studied against third instar larvae of Helicoverpa armigera. All the extracts showed feeding deterrent, larvicidal and pupicidal effects in a dose dependent manner. Significant antifeedant, larvicidal and pupicidal activities were observed only in hexane extract. The hexane extract was subjected to fractionation using silica gel column chromatography. Twelve fractions were obtained. Ninth fraction showed good antifeedant, larvicidal, pupicidal activities and disrupted adult emergence. LC(50) value was at 384.57 ppm for larval mortality. The active fraction at 1000 ppm concentration had 100% pupal mortality.

Antifeedant, larvicidal and growth inhibitory effects of ononitol monohydrate isolated from Cassia tora L. against Helicoverpa armigera (Hub.) and Spodoptera litura (Fab.) (Lepidoptera: Noctuidae).

Ononitol monohydrate isolated from the ethyl acetate extract of Cassia tora L. using column chromatography was evaluated for its antifeedant, larvicidal and growth inhibitory activities against Helicoverpa armigera and Spodoptera litura at different concentrations of 125, 250, 500 and 1000 ppm. Leaf disc no-choice method was used for the bioassay. The compound showed significant antifeedant, larvicidal and pupicidal activities against H. armigera and S. litura. The compound also prolonged the larval-pupal duration of the insect at all the tested concentrations. The activities were concentration dependent for both the insects. Ononitol could be used as an agent to prepare botanical new pesticidal formulations.

Ovicidal activity of Atalantia monophylla (L) Correa against Spodoptera litura Fab. (Lepidoptera: Noctuidae)

OBJECTIVE To evaluate the efficacy of Atalantia monophylla (A. monophylla) leaf in different solvent crude extracts and fractions against eggs of Spodoptera litura (S. litura). METHODS Hexane, ethyl acetate and chloroform solvent extracts of A. monophylla leaf and 12 fractions from hexane extract were screened at 5.0%, 2.5%, 1.0% and 0.5% for crude extracts and 1 000, 500, 250 and 125 mg/kg for fractions against the eggs of S. litura for the ovicidal activity. LC50 and LC90 were calculated using probit analysis. RESULTS Hexane crude extract showed maximum ovicidal activity of 61.94% at 5.0% concentration with a correlation value of r (2)=0.81, and least LC50 value of 3.06%. Hexane extract was fractionated using silica gel column chromatography and 12 fractions were obtained. Fraction 9 was active which showed maximum ovicidal activity of 75.61% at 1 000 mg/kg with the LC50 value of 318.65 mg/kg and LC90 value of 1 473.31 mg/kg. In linear regression analysis, significant and high correlation (r (2)=0.81%) was seen between concentration and ovicidal activity of hexane crude extracts and its active fraction. CONCLUSIONS As per our knowledge, this is the first report for ovicidal activity of A. monophylla against S. litura, A. monophylla could be used for the management of S. litura and other insect pests.

Bioefficacy of Ceasalpinea bonduc (L.) Roxb. against Spodoptera litura Fab. (Lepidoptera: Noctuidae)

Bioefficacy of hexane, chloroform and ethyl acetate extracts of the seeds of Ceasalpinea bonduc (L.) Roxb. was studied against third instar larvae of Spodoptera litura at 0.25, 0.5, 1, 2.5 and 5.0% concentrations. Significant antifeedant, larvicidal and pupicidal activities and least LC50 values were observed in chloroform extract. The chloroform extract was subjected to fractionation using silica gel column chromatography. Six fractions were obtained; among these, the third fraction showed high antifeedant, larvicidal and pupicidal activities at 1000 ppm concentration. Abnormalities in adults were also observed. All the activities were concentration dependent. C. bonduc could be useful in integrated pest management programme.

Ovicidal activity of Couroupita guianensis (Aubl.) against cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

There is a great demand for food with increasing population of the world. Many chemical fertilisers and pesticides are used to increase crop productivity. Over use of pesticides and fertilisers has affected the environment and non-target organisms severely; minor pests have become major destructive pests. Hence, eco-friendly approaches are needed. The present study reports the effect of hexane, chloroform and ethyl acetate extract of Couroupita guianensis on the eggs of Helicoverpa armigera. All the extracts showed ovicidal activity, and among them hexane extract showed 64.28% ovicidal activity with LC50 value of 2.62% and regression of (R 2) 83.5%. All the original data showed normality and homogeneity. The active hexane extract was fractionated; finally, eight fractions were obtained and studied at different concentrations. Among the fractions, fraction 8 showed 75% ovicidal activity with R 2 of 90%. It showed LC50 value of 322.94 ppm with χ 2 value at 0.5%. C. guianensis could be used in pest management programme.

Effect of pectolinaringenin, a flavonoid from Clerodendrum phlomidis, on total protein, glutathione S-transferase and esterase activities of Earias vittella and Helicoverpa armigera

Pectolinaringenin was isolated from chloroform extract of Clerodendrum phlomidis L. and was evaluated at 12.5 to 100 ppm concentrations for its effects on total protein, esterase and glutathione S-transferase (GST) activities of Earias vittella and Helicoverpa armigera. At 100 ppm, the compound reduced total protein content by 55.75% and 53.01% over control with IC50 values of 74.37 and 212.31 ppm in E. vittella and H. armigera, respectively. At 100 ppm it also reduced GST and esterase enzyme activities in E. vittella by 37.53% and 43.09% over control, with IC50 values of 133.00 and 111.76 ppm, respectively. It also reduced GST and esterase activities in H. armigera by 43.14% and 47.421% over control with IC50 values of 114.38 and 98.78 ppm, respectively. Data were analyzed for their normality using the Shapiro-Wilk test and Levene’s statistics to determine the significant deviation. Pectolinaringenin could be used for the management of agricultural pests.

Insecticidal and Repellent Activities of Toddalia asiatica (L.) Lam. Extracts against Three Major Stored Product Pests

Fumigant toxicity and repellent activity of Toddalia asiatica (L.) Lam. (Rutaceae) leaf and fruit extracts were screened against Callosobruchus maculatus (F.), Sitophilus oryzae (L.) and Tribolium castaneum (Herbst) adults. All the three solvent extracts of leaf and fruits recorded mortality and repellency against the three tested insects in a concentration dependent manner. C. maculatus was the most susceptible pest to the treatments. Lethal concentrations for 50 percent mortality (LC50) of C. maculatus, S. oryzae and T. castaneum were recorded as 39.19, 44.13 and 61.10 μL/L, respectively. Diethyl ether fruit extract exhibited 100% repellent activity against C. maculatus and S. oryzae and 92% against T. castaneum adults at 20 μL concentration. These results suggested that Diethyl ether fruit extract of T. asiatica can be used as an ecofriendly fumigant and repellent against C. maculatus, S. oryzae and T. castaneum.

Phagodeterrence and insecticidal activity of Hyptis suaveolens (Poit.) against four important lepidopteran pests

This study was carried out to evaluate the antifeedant and larvicidal activities of Hyptis suaveolens Poit. (Lamiaceae) leaves crude extracts and their fractions against four lepidopteran pests namely Helicoverpa armigera (Hbn.), Spodoptera litura (Fab.), Earias vittella (Fab.) and Leucinodes orbonalis (G.). Hexane, chloroform and ethyl acetate extracts were tested by leaf disc and fruit disc no-choice methods at 1% and 1,000 ppm concentrations for crude and fractions, respectively. Ethyl acetate extract of H. suaveolens exhibited the maximum antifeedant and insecticidal activity at 1% concentration against all the tested insects. It was subjected to fractionation using silica column chromatography with different combinations of hexane and ethyl acetate used as mobile phase. Among the 15 fractions obtained, fraction 2 showed the maximum antifeedant and insecticidal activity against all tested insects at 1000 ppm concentration. Preliminary phytochemical analysis of fraction 2 showed the presence of terpenoids and alkaloids. H. suaveolens could be considered as a safe and eco-friendly insecticide for lepidopteron pest management.

Biological properties of Endophytic Fungi

The endophytic fungus is have rich source of secondary metabolites which act as biological active agent in the higher plants. The fungal derivatives play vital part in human life and their compounds are the source of drug for cancer, microbial and viral diseases. The natural compounds from the endophytes acts as growth inhibitor of plant pathogenic organism. Endophytes are rich sources of natural products which are used in agriculture (plant growth and insecticidal), pharmaceutical industries and also used for phytoremediation.

Bio Efficacy of Atalantia monophylla (L) Correa (Rutaceae) against Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

Hexane, chloroform and ethyl acetate extracts of Atalantia monophylla were evaluated for their larvicidal and pupicidal activities against Spodoptera litura. Bioefficacy of A. monophylla leaf extracts were studied leaf disc no choice method at 0.5, 1.0, 2.5 and 5.0% concentration of crude extracts and 125, 250, 500 and 1000 ppm concentration of fractions against S. litura. The maximum larvicidal and pupicidal activities were noticed in hexane extract of A. monophylla. The hexane extract exhibited the least LC50 value of 2.01% for larvicidal activity and regression value (R 0.98 and Coefficients 9.33 ± 17.1) for concentration dependent larvicidal activity. The hexane extract was fractionated using increasing polarity of solvent system. Twelve fractions were isolated and were evaluated at four different concentrations. Maximum antifeedant, larvicidal and pupicidal activities was noticed in fraction 9 at 1000 ppm concentration. Ninth fraction exhibited concentration dependent antifeedant and larvicidal activities with liner regression of R 0.93, and 0.93 respectively. Least LC50 value of 340.27 ppm was observed in fraction nine for larvicidal activity. All the concentrations of 9th fraction showed good activity.