Species composition of rare weeds in the south of the Far East

Abstract

The results of monitoring (2016–2022) of the weed component of agrophytocenoses in the Primorsky Territory of the Russian Federation are presented. The species affiliation of rare weeds was determined, the average occurrence of which in soybeans, early grain crops and corn was less than 5% and with a maximum average abundance of 0.53 pcs/m2. A total of 58 low active weed species were identified, 29 of which were not previously found in the surveyed areas. The data on the average frequency of occurrence of rare species, the density of infestation by them of all surveyed areas and the results of monitoring of crops of individual crops are analyzed. It has been established that the species diversity and abundance of rare weeds depend on the characteristics of cultivated crops. Weed species confined to individual crops and weeds growing everywhere have been identified. Eight species were recorded in areas under all crops: Galinsoga parviflora Cav., Potentilla anserina L., Gnaphalium uliginosum L., Arctium lappa L., Crepis tectorum L., Inula salicina L., Avena fatua L. and Poa pratensis L. Exclusively in 26 rare species were noted in soybean crops. In total, 57 low-active species were recorded in soybean agrocenoses, 26 species in corn crops, and 18 species in early grain crops. The most problematic species with increased occurrence in recent years, representing a potential danger for crop production in Primorsky Krai, have been identified.