Weeds in the Southern Trans-Urals

The analysis of weed species composition in the Southern Trans-Urals was presented. The studied segetalflora included 127 species, 91 genera and 26 families. The most multi-species families were Asteraceae (23 species), Brassicaceae (14 species), Fabaceae and Poaceae (13 species). The most multi-species genera were Artemisia, Brassica and Vicia.The single-species genera in the segetal flora of the South Trans-Urals was up to 73 %. The amount of alien plants was 58%. We classified 11 species as highly active weeds. They had a high coverage (25–40 %), medium or high occurrence (inmore than 41 % of the surveyed field crops) and were found in all crops. Most weeds was inactive (103 species or 81 %).