Alexander Ruchin¹, Evgeniy Lobachev¹ , and Sergei Lukiyanov^1,2

¹ Joint Directorate of the Mordovia State Nature Reserve and National Park "Smolny", Saransk, 430005, Russia

² National Research Mordovia State University, Russia

Abstract

A study was conducted to investigate the distribution and significant increase in the abundance of Lymantria dispar within the foreststeppe zone of European Russia, encompassing the regions of Ryazan, Moscow, Vladimir, and Ulyanovsk. The examination of hotspots associated with this pest during the year 2023 involved an analysis of data derived from diverse sources. The investigation encompassed an assessment of plant species that either attracted or repelled the pest's caterpillars under natural conditions. The defoliation phenomenon was observed to vary across distinct plant species, with notable instances of extensive destruction identified on Betula, Quercus robur, Populus tremula, and various Salix species at multiple observation plots. Conversely, conifers such as Larix sibirica, Picea abies, Pinus sylvestris, and certain invasive (introduced) species, including Acer negundo, Elaeagnus argentea, Hirrarchaea rhamnoides, and Syringa vulgaris, exhibited an absence of caterpillar presence.