In field tests conducted at Saskatoon, Melfort, Scott, and Shellbrook, crucifer species differed in their levels of damage from crucifer-feeding root maggots of the Delia species complex. Sinapis alba was less injured than B. carinata, B. rapa, B. juncea, or B. napus. Root diameter may play a part in this difference in susceptibility. Differences in root injury levels within species occurred frequently, but were less consistent than among species. Location and year strongly influenced maggot infestation and damage levels.