Inhibition of oviposition by volatiles of certain plants and chemicals in the leafhopperAmrasca devastons (distant).

Oviposition by the leafhopperAmrasca devastans (Distant) on its susceptible host plant, cotton (Gossypium hirsutum var. PS-10), was inhibited by the volatiles of certain plants and by the vapors of some chemicals occurring in various plants when these were presented at a distance from the ovipositional substrate. The effectiveness of the volatiles of the plants for inhibiting the oviposition decreased in the order: eucalyptus > coriander=castor=tomato > lime,Ocimum being without effect. Among the volatile plant chemicals tested, the inhibitory effects decreased in the order: citral=carvacrol > citronellol=farnesol = geraniol=eucalyptus oil > neem oil=Cymbopogan oil. These chemicals served as volatile antiovipositants and did not reduce the arrival/stay of the insects on the host plants. Carvacrol had a slight toxic effect on the nymphs, but none of the volatiles was toxic to the adults.