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.

Synthesis of thymyl esters and their insecticidal activity against Spodoptera litura (Lepidoptera: Noctuidae).

Background: Thymol, a natural phenolic monoterpene originating from Thymus vulgaris, is recognized as a safe and potent botanical insecticide to many insects. The structural modification of thymol into thymyl esters is a potential approach for the development of novel insecticides, which showed more toxicity than thymol. However, there are no reports on the insecticidal activity of thymyl esters to control Spodoptera litura.

INSECTICIDAL ACTIVITIES OF THYMOL ON EGG PRODUCTION AND DEVELOPMENT IN THE DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA (LEPIDOPTERA).

The insecticidal activity of thymol was evaluated in the laboratory against third instar Plutella xylostella by topical application. Our previous results described mortality in P. xylostella by thymol and the present study continues investigation for its possible efficacy on egg production and development in surviving treated P.