Species diversity and abundance of aphids on spring rapeseed at the Menkovo branch of Agrophysical Research Institute

In recent years, in the North-West region and the Leningrad region in particular, there has been a deterioration in the phytosanitary condition of spring rapeseed sowings, caused by an increase in the areas under this crop and an increase in the duration of its cultivation in farms. The aim of the research was to study the species diversity, abundance, structure of the aphid complex and population dynamics in spring rapeseed sowings at the agroecological station of the Menkovo branch of the Agrophysical Research Institute (Leningrad region). The research was carried out in 2021–2022 with the use of yellow water traps and route survey of the sowings. Aphids were counted in intervals of 7–8 days in July and the first twenty days of August. The aphid complex was characterized by high species diversity (15 species) and low abundance (2.0–2.1 specimens/trap). The numerical majority were species whose food specialization was associat-ed with rapeseed plants (43.5%), the remaining part was determined by the presence of weed vegetation (17.2%) and nearby agricultural crops (39.3%). Cabbage and mustard aphids were the dominant species, accounting for 23.5% and 19.8% of specimens, re-spectively. Mustard aphids were mainly caught in yellow traps in June, while cabbage aphids were caught in August. The maximum species diversity and abundance of aphids in spring rapeseed sowings were observed in the mid-July at the optimal sowing date (May 11, 2022) and in early August at the late sowing date (May 25, 2021). The higher number of cabbage aphid specimens was observed at the late sowing date of rapeseed compared to the optimal one.