Abstract: The relation of chemical communication between the host-herbivore-natural enemies is the basis of existence of the member in the food chain. The chemical communication between tea plant and the three major insect pests (tea geometrid, tea aphid, tea leafhopper) as well as the seven natural enemies was investigated by the authors. Results indicated that the location of insect pest on the tea plant depended on the volatiles emitted from the tea shoots, such as the z-3-hexen-1-ol, linanool, n-pentanol etc. Bioassay and EAG estimation showed that these compounds showed strong attractiveness and electrophysiological response to tea pests, however, they showed only a weak activities to the natural enemies. The metabolism in tea plants was changed and released the specific synomone after damaged by the pests. For example, the damage of tea geometrid induced more C₅-C₆ aldehyde compounds liberated and tea aphid damage induced the liberation of benzyaldehyde. The damage of tea shoots by tea leafhopper induced the release of 2,6-dimethyl-3,7-octadien-2,6-diol and indole. These compounds showed a strong attractiveness and electro-physiological response to their respective natural enemies under a very low concentration of 10^-6-10^-9βg/ml, however, they showed only a weak or no activities to leafhopper. The enzymes in the oral regurgitate secreted by the tea pests was the elicitor inducing the release of specific volatile synomone from tea shoots. These synomones possessed the systemic activity of translocation in tea plant.

Key words: Chemical ecology, Chemical communication, Synomone, Tea geometrid, Tea aphid, Tea leafhopper