Perennial dicotyledonous weeds of the Primorsky Region

The aim of this study is to summarize the results of herbological studies conducted by the Far Eastern Research Institute of Plant Protection from 2013 to 2024 to determine the species composition of dicotyledonous perennial weeds and their infestation density in fields in the Primorsky Region. Surveys of soybean, corn, and early grain crops were conducted annually over an area of 2,700–12,300 hectares during the period of mass weed emergence (late June – early July) and later, during the flowering phase, for final identification. This study yielded data on the species composition, prevalence, and abundance of perennial dicotyledonous weeds in the crops of the main agricultural crops in the Primorsky Region. A total of 43 perennial dicotyledonous weed species belonging to 16 families were identified. The perennial weeds were divided by root system structure, and predominant groups – rhizome and taproot plants – were identified. The most common weed, annually recorded in all surveyed areas, was Sonchus arvensis L., with an average occurrence of 82.8 % and abundance of 4.3 pcs/m2. Artemisia L. spp., Equisetum arvense L., and Cirsium setosum (Willd.) Bieb. were also widespread, annually recorded in all studied agrocenoses on 50–70 % of the surveyed fields. The group with an occurrence of 20–50 % included Vicia cracca L., Taraxacum mongolicum Hand.Mazz., Glycine soja Siebold et Zucc., Stachys aspera Michx., Plantago uliginosa F.W., Trifolium L.: T. pratense L., T. lupinaster L., T. campestre Schreb., T. repens L., T. hybridum L., Rumex crispus L. Wild soybean, with its exceptionally high invasive potential, was identified as the most potentially dangerous weed species for agrocenoses of the Primorsky Region.