SATURATED-HYDROCARBONS AS KAIROMONAL SOURCE FOR THE EGG PARASITOID, TRICHOGRAMMA-CHILONIS ISHII (HYM., TRICHOGRAMMATIDAE)

Studies on the effect of saturated hydrocarbons on parasitization by t he egg parasitoid Trichogramma chilonis Ishii were carried out in the laboratory and net house. Bioassay of 11 hydrocarbons, viz. pentadecan e, heptadecane, ecosane, heneicosane, docosane, tricosane, tetracosane , pentacosane, hexacosane, octacosane and hexatriacontane, were carrie d out under controlled conditions in the laboratory. These were also t ested on potted maize plants in a net house. Among the saturated hydro carbons, octacosane recorded the highest parasitoid activity index fol lowed by docosane and tricosane. However, tricosane caused the highest percentage of parasitization, which was at par with octacosane and do cosane. A positive correlation was found between concentration and kai romonal activity only in case of tricosane. In the net house, tricosan e recorded the highest parasitization. Response of the parasitoid to e gg cards treated with hydrocarbons decreased with increase in distance between the release point and host eggs. No parasitization was observ ed in host eggs placed at 8 m and 10 m away from the point of release except in the case of tricosane and pentacosane.