Effect of isolated compounds from Combretum trifoliatum on toxicity and detoxification enzymes in Nilaparvata lugens.

The brown planthopper (BPH) Nilaparvata lugens (Stål) is a major insect pest of Oryza sativa that causes crop yield loss in tropical regions, including Thailand. In this study, the crude ethanolic extract of the leaves and branches of Combretum trifoliatum , its active isolated components, apigenin and camphor, and Finopril were tested for their ability to control the first to fifth instars of N. lugens.

Phenolic secondary metabolites from Acorus calamus (Acorales: Acoraceae) rhizomes: the feeding deterrents for Spodoptera litura (Lepidoptera: Noctuidae).

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is one of the most destructive pests of various crops cultivated in Thailand. Spodoptera litura larvae, at early stages, attack the leaves and feed on every part of infested crops in later stages. Acorus calamus essential oil contains toxic asarones, which are generalistic cytotoxic compounds.

Insecticidal and growth inhibitory effects of some thymol derivatives on the beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae) and their impact on detoxification enzymes.

Background: Thymol is a known natural product with insecticidal activity against several insect species. A recent study on structural modifications of thymol to thymyl esters and their efficacy against Spodoptera litura suggested that such an approach could develop generalized novel insecticides/insect growth inhibitors and requires further studies to establish the efficacy against lepidopterans.

Results: Thymol and structurally modified eight esters were evaluated against beet armyworm, Spodoptera exigua using the topical application.

The Study of Isolated Alkane Compounds and Crude Extracts From Sphagneticola trilobata (Asterales: Asteraceae) as a Candidate Botanical Insecticide for Lepidopteran Larvae.

The antifeedant and contact toxicity of Sphagneticola trilobata L. (Asterales: Asteraceae) extracts and isolated alkane compounds were investigated. Leaves of S.

EFFECTS OF AZADIRACHTIN ON CUTICULAR PROTEINS OF SPODOPTERA LITURA (LEPIDOPTERA: NOCTUIDAE) VIS-A-VIS THE MODES OF APPLICATION.

Azadirachtin is a known botanical insecticide with multiple modes of action. Whether these effects have any relation with the modes of application, specifically during ecdysis process, has been the objective of the present study and accordingly the impairment, if any, among cuticular proteins of Spodoptera litura (Fab.) was determined.

Acute, sublethal and combination effects of azadirachtin and Bacillus thuringiensis toxins on Helicoverpa armigera (Lepidoptera: Noctuidae) larvae.

The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin WG, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture.

Bioefficacy and mode-of-action of some limonoids of salannin group from Azadirachta indica A. Juss and their role in a multicomponent system against lepidopteran larvae.

Biological activities of the salannin type of limonoids isolated from Azadirachta indica A. Juss were assessed using the gram pod borer Helicoverpa armigera (Hubner) and the tobacco armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae.

Biological activity of volatile di-n-propyl disulfide from seeds of neem, Azadirachta indica (Meliaceae), to two species of stored grain pests, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst).

Head space volatiles, including 73% di-n-propyl disulfide, were collected from freshly crushed neem seeds. This compound along with previously reported diallyl disulfide (di-2-propenyl disulfide) were toxic when applied topically or as a fumigant to Tribolium castaneum adults and 8-, 12-, and 16-d-old larvae, and Sitophilus oryzae adults. Di-n-propyl disulfide significantly decreased the growth rate and dietary utilization with moderate inhibition of food consumption in both insects.

Antifeedant effects of the limonoids from Entandrophragma candolei (Meliaceae) on the gram pod borer, Helicoverpa armigera (Lepidoptera: Noctuidae).

The biological activity of the limonoids prieurianin and epoxyprieurianin isolated from Entandrophragma candolei (Harms) (Meliaceae) and their respective acetates was assessed using the gram pod borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae). The compounds exhibited strong antifeedant activity in a diet choice bioassay with epoxyprieurianin acetate being most effective with 48.3 ppm deterring feeding by 50% (DI50) and prieurianin the least effective (DI50 = 91.

6beta-hydroxygedunin from Azadirachta indica. Its potentiation effects with some non-azadirachtin limonoids in neem against lepidopteran larvae.

The biological activity of 6beta-hydroxygedunin isolated from Azadirachta indica A. Juss. was assessed using the gram pod borer, Helicoverpa armigera (Hubner), and Asian armyworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), alone and in combination with other limonoids, gedunin, salannin, nimbinene, and azadirachtin.