Fig. 1. Frequency distribution of mean exit holes per pod from larvae of C. obstrictus in 230 hybrid genotypes derived from crosses of S. alba x B. napus. The dotted line indicates the cutoff for lines selected for further susceptibility assessment (mean of 0.05 exit holes per pod), and the dashed line indicates the approximate position of the commercial canola cultivar, B. napus cv. Q2 (mean of 0.24 exit holes per pod).