In the process of host location and selection several cues associated with host’s play a major role. Volatile compounds emitted by plants as a consequence of herbivore activities are often attractive to insect natural enemies including the Hymenopteran egg parasitoids, Trichogramma species. We studied the plant - parasitoid interactions where the plant surface chemicals act as infochemicals that attract or arrest the parasitoids for egg parasitization and strategically help in preventing the pest infestation. The leaf surface chemicals of R. communis, damaged due to the feeding of the host, Achaea janata (L) (castor semilooper) (Lepidoptera: Noctuiidae), and a non – host, Serpentine leaf miner Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) were evaluated for their

influence on host location, host acceptance and ovipositional behavior against the egg parasitoid, T. chilonis in laboratory bioassays. The A. janata damaged leaf emissions had synomonal effects on the parasitoid and induced orientation and oviposition, whereas, the surface chemicals from the plant infested with non-host L. trifolii ceased to produce any such effects. The maximum egg parasitization was observed in A. janata infested castor leaf extracts compared to the leaf miner infested or normal healthy castor leaf extracts. The results are interesting in the context of tritrophic interactions between the pest, parasite and the host plant and are useful in biological control of insect pests.