Studies revealed that numerous species of noxious insects, particularly those from the group of so-called harassing and secondary pests, found favorable conditions for their development in areas under permanent impact of industrial air pollution. The most numerous and most important species in pine stands is Exoteleia dodecella L., the larvae of which at first mine needles, then destroy the buds. Feeding by this pest causes deformations as a result of which younger trees acquire a shrubby form, while older ones are umbrella-shaped. Among the primary pests, Acantholyda nemoralis Thoms. and sometimes Lymantria monacha L., may occur more abundantly in the areas containing little industrial emissions. In older stands secondary pests which could be divided into two groups were of great economic importance. The first group includes Phaenops cyanea F., Pissodes piniphilus Hbst., and Paururus juvencus L. which infest trees in gappy stands, strongly thinned ones, and those adjoining industrial plants.