A low-molecular-weight, sugar-like compound other than glucose, fructose, sucrose, or myo-inositol showing lipophilic nature was isolated from the EtOH extract of Acacia nilotica. The structure of the compound was determined by spectral methods. This alicyclic polyalcohol was found to be D-pinitol (= 3-O-methyl-D-chiro-inositol; 1). The configuration of the compound was confirmed by single-crystal X-ray analysis. The compound 1 is known from Soybean, Australian mangroves, Fagonia indica, Arachis hypogaea, etc., but we have isolated this compound for the first time from the aerial parts of A. nilotica. Very few references have been cited for compound 1 for its entomological activity, and there are no reports on mosquitoes. Therefore, the crude extracts of A. nilotica were tested for its biological activity against mosquito larvae. Acetone extract at 500-ppm concentration showed chronic toxicity against Aedes aegypti and Culex quinquefasciatus IVth instar mosquito larvae. Such a biological activity has been observed for the first time for this plant. This study could be a stepping stone to a solution for destroying larval species as well as consumption of such a widely grown, problem weed, A. nilotica. This larvicidal agent, since it is derived from plant, is eco-friendly, cost effective, non-hazardous to non-target organisms and would be safe unlike commercially available insecticides.

The larvicidal activities of various fractions of the hexane extract of the seeds of Sterculia guttata against larvae of Aedes aegypti and Culex quinquefasciatus were determined. Bis(2-ethylhexyl) benzene-1,2-dicarboxylate (1) was identified as one of the active principles, displaying chronic toxicity against both types of larvae, with LD50 values of 79 and 64 ppm, respectively.

The external morphology and peripheral olfactory responses of antennal chemoreceptors of Trichogramma chilonis Ishii (Hymenoptera:Trichogrammatidae) to host related stimuli were examined by SEM and EAG technique respectively. The antennae of male and female T. chilonis reveal strong sexual dimorphism in structure as well as in types, density and distribution of individual sensillar types. The female antennae are characterized by the presence of a single uniporous sensilla on the apical tip of the dome and numerous multiporous pitted sensilla. Sensilla common to both males and females include the multiporous plate sensilla, the peg sensilla and trichoid sensilla. Differences between males and females occur with respect to their EAG profiles to 22 chemicals commonly found in plants viz.leaf extracts of three host plants of Helicoverpa armigera (cotton, chickpea and pigeon pea) and hexane scale extracts of adult males and females of H. armigera. Individually, the largest peak amplitudes in females were obtained with citronellal, phytol, caryophyllene, R-(+)-limonene, linalool, carvacrol and citronellol while in males citronellol, caryophyllene, linalool, R-(+)-limonene and amyl acetate caused the highest response. Among the different chemical classes, the largest peak amplitudes in females were obtained with oxygenated monoterpenes, while in males, fatty acid derivatives caused the highest response. In both males and females, the hydrocarbon monoterpenes caused the least response. Thus, the wide spectrum response of Trichogramma chilonis, to a wide group of chemicals belonging to different chemical classes, though varying, nevertheless suggests that using plant information enhances its parasitization efficiency.

Several terpenoids and oils were screened for vapour toxicity and repellency against the termite, Odontotermes brunneus. In toxicity tests, knockdown time KT 50 and KT 90 values were derived at 5 mg/cm 2 . For repellency screening, a new experimental setup was designed and effective time ET 5n and ET 9( | values were determined at 2 mg/cm 2 . Among the compounds screened, eucalyptus oil produced the fastest knockdown (KT 50 24.8 min) while (5-ionone was found to be the least effective (KT 50 536.0 min). Terpeneol (anhydrous) afforded maximum persistence of 338.0 min, whereas the least persistence was obtained from linalool (78.9 min) which prevented 50% of the population from crossing over the treated barrier (ET 50 ). Resume-Plusiers terpenoides et huiles ont ete passes au crible pour la toxicite de leurs vapeurs et le pouvoir repulsif contre le termite Odontotermes brunneus. Dans les essais de toxicite, les valeurs pour le temps knockdown KT50 et KT 90 ont ete deduites a 5 mg/cm 2 . Pour le test de repulsivite, un nouveau dispositif experimental a ete conc,u et les valeurs de periode d'efficacite ET 50 et ET 9 o ont ete determines a 2 mg/cm 2 . Parmi les composes passes au crible, I'huile d'eucalyptus a produit le knockdown le plus rapide (KT 50 24,8 min) tandis que (3-ionone s'est revelee la moins efficace (KT50 536,0 min). Le terpenol (anhydre) a donne une persistence maximale de 338,0 min, tandis que la plus faible persistence a ete obtenue avec le linalool (78,9 min), lequel a empeche 50% de la population de franchir la barriere traitee (ET ;o ).

The major non-azadirachtin limonoids such as gedunin (1), epoxyazadiradione (3), nimbocinol (4), and nimolicinol (5) from Azadirachta indica A. Juss ('neem') and their derivatives were evaluated for their toxic action against fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus Say. Gedunin exhibited 100% toxic action against both the mosquito larvae at 50 and 10 ppm. Epoxyazadiradione and epoxynimolicinol also showed significant toxicities (> or =50%) against larvae of both mosquito species at 50 ppm. These neem limonoids can have benefits in mosquito-control programs.