PHENOLOGY OF THE DEVELOPMENT OF THE CEREAL LEAFROLLER (CNEPHASIA PASIUANA) IN THE EASTERN CISCAUCASIA IN 2023–2025

Abstract

In the southern regions of the Russian Federation, there is an increase in the harmfulness of the cereal leafroller as a new pest of winter wheat. As a species, it is widespread across Eurasia, but until 2018, it had not been recorded in the Eastern Ciscaucasia. The biology, including the phenological characteristics of the leafroller, remain unstudied. The nature and extent of damage caused by this phytophagous insect have been poorly studied. Plant protection specialists often attribute damage to ears of grain caused by the leafroller to the feeding of the sunn pest and do not attach much importance to pest control. Firm thresholds for damage have not been established, nor have the yield losses caused by the leafroller been determined — these figures vary widely among different authors. They are often overestimated in the scientific literature. In 2023–2025, the first observations of the phenology and other biological characteristics of the cereal leafroller were conducted in the arid zone of the Stavropol Territory, in the Novoselitsky District. This pest has significant differences in its biological cycle and phenology from other winter wheat pests, including the sunn pest, cereal leaf beetle, cereal sawflies, and other common crop inhabitants. It was established that the cereal leafroller overwinters as a first-instar larva (caterpillar) in forest belt trees, hiding under bark crevices immediately after hatching. Temperature thresholds for larval activation after overwintering and migration to winter wheat crops were determined. Weather conditions varied significantly over the three years of observation, affecting the pest's phenology and other parameters. Weather conditions play a dominant role in determining the abundance and damage of the leafroller. In this regard, when developing an integrated leafroller control system, the most important role should be given to monitoring the pest from the beginning of migrations in the spring until the transition to vulnerable stages of development, when it is possible to carry out chemical and biological protective measures to prevent crop losses.