There is a good number of tree species that always occur in nurseries and plantations, each of which may be a host for numerous insect pests. However, to develop effective control measures the insect must be responsible for economic losses large enough to justify the costs of materials and labour. Insect species, which normally occur in low densities, are of little or no economic consequence. In such cases, control measure would be justified if the costs are minimal. The insects that do cause great damage to forest plants either consistently or sporadically should be the focus for possible implementation of control programmes to develop long-term protection. A good amount of research has been undertaken on the insect pest problems of forestry species and to develop control measures. The key insect pests found on forest plants are grouped as soil-inhabiting insects, defoliators, sap suckers and borers. To combat these insect pests, safer chemical pesticides have been standardised and are successfully being practiced to prevent insect damage. Emphasis is now being laid on developing biocontrol strategy (screening resistance, biopesticides and classical biological control) against major insect pests. The serious problems of key insect pests of promising forestry species and the strategy of their management are mentioned in this chapter.