Note the blackened veins. Figure 9 Advanced stages of bacterial leaf spot of cauliflower showing brown, papery areas surrounded by yellow leaf tissue. Note the holes in the leaf blade, giving the plant a ragged appearance. Broccoli heads having depressions in which water collects often become infected by soft rot bacteria in the field. Tip burn in cabbage heads can lead to subsequent breakdown by soft rot bacteria.
Soft rot is a severe problem in storage and transit as well as in the field.
Every effort should be made to minimize wounding during harvest and to avoid rinsing or chilling crucifers with unclean water. Figure 10 Brown, mushy, soft-rotted tissue on this cabbage head is caused by bacterial soft rot organisms. Figure 11 Cauliflower head on right has bacterial soft rot bacteria and is also infested with seed corn maggot larvae in the brown, decayed pockets. Breeding cabbage for resistance to black rot is in progress, based on Asian material such as Early Fugi. Resistant inbred lines are now available to seedsmen from the University of Wisconsin, and many tolerant cultivars of cabbage are marketed commercially.