The composition of herbivore induced plant volatiles (HIPVs) varies between different plant species, varieties, growth periods and different tissues within a plant. The characteristics of HIPVs depend on the species of herbivore, which herbivore instars are present, the degree and pattern of damage and some other environmental factors also. The release of HIPVs from damaged plants is much higher than that from healthy plants, making them more likely to be detected by herbivores, their natural enemies, neighboring plants and so on. HIPVs could be used to manipulate the tri\|trophic interaction between plant, herbivores and natural enemies of herbivores, thereby strengthening the survival capability of the plant. The role of HIPVs in host searching and population regulation and the applications of this to pest control are summarized in this paper. Some related study questions are also discussed.