Effect of biological agents on changes in the number of cotton bollworm (Helicoverpa armigera Hbn.) in the Cenosis of corn (Zea mays L.)

Corn (Zea mays L.) is one of the most important crops. The most significant damage to the corn crop is caused by the cotton bollworm (Helicoverpa armigera Hbn.), which harms more than 60 crops and feeds and reproduces on 67 species of wild plants. The purpose of this work was to evaluate the effectiveness of biological preparations against this dangerous pest. The evaluation was conducted over two years (2023–2024) in the central zone of the Krasnodar Territory (Russia), at the Kononenko Farm in the Dinskoy district, on corn crops. The studied preparations Biostop, Zh; Akkar, Zh, and Bioslip BV, Zh were compared with the reference bioinsecticide Lepidocide, P. The production assessment was carried out on an area of 2 ha in a triple repetition using the preparation Biostop, Zh. The biological effectiveness of the tested preparations was determined by the number of caterpillars per ear of corn before and after treatment. The treatment time was determined using pheromone traps with a synthetic analog of the cotton bollworm pheromone. It was shown that biological preparations reduced the number of cotton bollworms. On average, over two years, the effectiveness of Bioslip BV, Zh was 40.2-62.2%; Akkar, Zh – 69.9-83.2%; and Biostop, Zh – 73.4-90.0%. Production tests of Biostop, Zh showed that it limited the number of cotton bollworms during the growing season. Thus, on 27.07.2023, the number of caterpillars in the control variant was 18.5 specimens/50 plants, and in the experimental variant, 4.7 specimens/50 plants. In 2024, the values were 12.4 and 3.4 specimens/50 plants, respectively. The two-year data obtained showed high biological effectiveness of Akkar, Zh, and Biostop, Zh.