Olfaction is a molecular sense, in which information carried in airborne chemicals is transformed into patterns of brain activity that underlie odor perception. It is probably the most important sense for survival of most animal species ranging from insects to mammals. Detection and localization of food, avoidance of toxins and predators, and communication with cohorts and mating partners through volatile pheromones are examples of the range of olfaction dependent behavior. Olfaction in insect, both medical and agricultural fields, is well documented today. That wide knowledge of insect olfaction (behaviour), especially in agriculture, has contributed to the development of the Integrated Pest Management (IPM) strategies, especially the use of semiochemicals for luring, trapping and killing of insect pests. The present literature review addresses the following general subjects: notion of the pest, importance of the sensilla in insect life, general mechanism of chemical signals transduction, odor identification and discrimination in insects, chemical messengers (pheromones and allelochemicals), insect-plant interactions, ratio-specific odor recognition, and evolution in pest-control strategies and the use of plant extracts in protecting stored-products. The purpose is to contribute in helping beginners in the modern agricultural entomology field for rapid familiarization with these terms frequently used in IPM strategies.