Assessment of Agroecological Factors Shaping the Population Dynamics of Sunn Pest (Eurygaster integriceps Puton) in Kazakhstan

Abstract

The Sunn pest (Eurygaster integriceps Puton) ranks among the most harmful pests affecting wheat yield and grain quality in Kazakhstan. In particular, it poses a serious threat to regions in which winter wheat cultivation is dominant. Climate change, parasites, predators, and recent transformations in agriculture and human activities in Kazakhstan and throughout Central Asia have significantly influenced the population dynamics of the Sunn pest. This study reports the findings on Sunn pest population dynamics in Kazakhstan’s winter wheat growing regions from 2022 to 2024, based on surveys of 233 hectares across four regions. In total, 1753 specimens of the Sunn pest were studied. The obtained results were analyzed in comparison with historical data (1991–2020) and recent findings in this field. We found that a combination of ecological factors are the main determinants of the Sunn pest population dynamics in different regions of the country. The pest population increased in seasons with optimal temperature (sum of effective temperatures—SET) and humidity conditions (hydrothermal coefficient—HTC), as well as when wheat cultivation areas and forest belts expanded. Moreover, the results highlighted that the pest population is controlled by the activity of egg parasites (Telenomus) in the south, unfavorable weather conditions during overwintering in the east and west, and the growing of resistant varieties in the southeast of the country. Compared to wild grasses, wheat crops increased the reproductive potential of the pest.