Lygus species were sampled from the flowering heads and developing racemes of three species of Brassica [B. campestris L., B. juncea (L.) Coss., and B. napus L.] and two species of Sinapis (S. alba L. and S. arvensis L.) from cultivated fields during a survey from Prawda, Manitoba, to Lethbridge, Alberta. Lygus elisus Van Duzee and L. borealis (Kelton) were the most prevalent and abundant in Alberta and Saskatchewan; L. lineolaris (Palisot) was the most prevalent and abundant in Manitoba. Lygus rubrosignatus Knight, L. solidaginis (Kelton), and L. shulli Knight, previously unreported on Brassica, occurred in low numbers at most sites in Alberta and Saskatchewan.