The influence of wheat thrips on the quality and grain yield of spring soft wheat in the southern forest-steppe of Western Siberia

In the context of global climate change and intensification of agricultural production, issues of plant protection from pests are of particular importance, among which wheat thrips (Haplothrips tritici) occupies one of the leading places. The article presents the results of long-term research (2021–2023) conducted at the Omsk Agricultural Scientific Center, devoted to the study of the effect of wheat thrips on the yield and grain quality of spring soft wheat of the Omskaya 42 variety in the southern forest-steppe of Western Siberia. The main objective of the work was to assess the relationship between the level of mineral nutrition of plants, the number of pests and the effectiveness of various crop protection schemes. The research found that the application of nitrogen fertilizers at a dose of N35 contributed to an increase in the number of wheat thrips by 1.5 times compared to the unfertilized background (84 and 57 individuals per 10 net swings, respectively). Use of the insecticide "Espero, K.S." provided a 36–50% reduction in thrips numbers, but repeated treatments were necessary due to the high rate of population recovery. The highest yield (2.50 t/ha) was achieved with the integrated use of chemicals, including the introduction of herbicides, fungicides, insecticides and foliar feeding (urea + Aqualis). At the same time, the yield increase on a fertilized background was 0.58 t/ha (30%) compared to the control. Grain quality indicators (protein content – 16.7–17.6%, gluten – 32.1–35.8%) met the requirements of class 1, but the grain nature (681–689 g/l) remained below the standards, which is due to the extremely dry conditions of the growing seasons. The practical significance of the work lies in the development of recommendations for optimizing a differentiated approach to the application of nitrogen fertilizers, taking into account the risk of increasing the number of pests, and the development of adaptive plant protection systems that combine chemical and agrotechnical methods.