Chemical communication is very important for survival and reproduction in insects. The successful survival of insects depends to a large extent on the ability to detect and recognize environmental signals. We can manage the insect pest populations by eco-friendly methods by understanding the chemical communication systems which lie among the host trees, pests, and natural enemies. Persimmon is the largest fruit tree in acreage in Korea. Many insect pests are attacking various part of persimmon. Major insect pests of persimmon in Korea are Riptortus pedestris, Halyomorpha halys, Plautia stali as hemipterans, Stathmopoda masinissa, Euzophera batangensis, Conogethes punctiferalis as lepidopterans, There are also some minor insect pests including Homona magnanima, Apolygus spinolae, Synanthedon tenuis, bark beetles et cetera. Some of these produce sex pheromones to attract conspecific females or produce aggregation pheromones to gather conspecific individuals. Interestingly, some insect pests are using the semiochemicals of other species, pheromones or floral scents, as kairomones to find hosts or oviposition sites. These relationships in chemical communications at persimmon ecosystem will be discussed using our research results and others so far.