The article deals with the problem of the spread of the most dangerous pest in winter wheat in Ukraine - Sunn pest
(Eurygaster integriceps Put.). The features of its development in the Right-bank Forest Steppe of Ukraine were studied.
Morphological peculiarities of imago populations of the Sunn pest have been investigated. Researches revealed variability
of length and stability of width of body of a pest by years. The study of the seasonal dynamics of the number of Sunn pest
showed a gradual increase in the population by the stages of winter wheat development. The dependence of the bug on the
meteorological conditions of the research years was noted. The structure of the pest population by phenotypic features such
as the nature of the imago pattern has been studied. Phenotypes are distinguished by the degree of noticeability of the trait.
Sunn pest, winter wheat, seasonal dynamics, phenotypic population structure