Environmental and anthropogenic factors influencing key cabbage Lepidopteran pests in the southwestern Siberia

Abstract

The lepidopteran pest community composition on cabbage (Brassica oleracea L. ) as the main vegetable crop in the conditions of southwestern Siberia was presented. In 2015-2019, the dominant cabbage pests were diamondback moth (Plutella xylostella L. ) and cabbage moth (Mamestra brassicae L. ). The continuous application of insecticides against the cabbage pests along with climatic factors led to a change in insect species community composition. This was manifested as an increase in the number of the diamondback moth and a decrease in the abundance of other Lepidoptera species. The mean number of diamondback moths varied from 0.06 (in a year of low numbers) to 1.4 specimens per plant (in years of outbreaks), and for cabbage moth - 0.12 (2015) and 0.43 (2016), respectively. In commercial cabbage field, both egg-laying and caterpillars of Pieris brassicae L. and P. rapae L. were found as a single individual. During the years of research, we noted earlier diamondback moth and cabbage moth appearance dates in the field. More frequent diamondback moth outbreaks were observed. The period of cabbage damage by the diamondback moth lasted longer than usual during the growing seasons due to an increase in the number of insect generations in the conditions of the southwestern Siberia. paper 2