This book illustrates how the potential use of the pheromones (scouting, monitoring, or optimal timing of insecticide application) depends on both the pest and the pheromone. The case of the three most important corn pests for the region of South Eastern Europe: wireworms, western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte and European corn borer (ECB) Ostrinia nubilalis Hubn are discussed herein. Pheromones should not be used to determine intensity of the infestation, but to set the period of the maximum incidence of the moth, on the basis of which information the period of the application of insecticides is set.