Chemical ecology of insects evolved as a discipline concerned with plant insect interactions and with a strong focus on intraspecific pheromone-mediated communication. Plants produce a variety of secondary metabolites as chemical barriers against herbivores. Insects are highly adapted to these allelochemicals and use them as the specific host-finding cues, defensive substances of their own and also sex pheromones or their precursors by selectively sensing, processing these phytochemicals. The most developed and successful techniques are those based on insect pheromones. The high sensitivity of insects to pheromones and the specificity of them makes them a powerful tool in insect management. Pheromones have been used successfully as lures in mass trapping of insects and attract and kill techniques in many species. Commercially, sales of semiochemicals (mainly pheromones) represent a very small fraction of the current global market for pest control products. At present, about half of the total sales of semiochemical-based products are in the form of pheromone lures and traps for monitoring purposes, while most of the remainder are for mating disruption products.