If disease development is extensive, leaves may take on a blighted effect due to the numerous infection sites. Early symptoms on transplants may resemble bacterial leafspot symptoms. Severely diseased seedlings may be stunted or die. The pathogen survives between crops on weed hosts or as resilient oospores in crop residue.
Spores are airborne.
Some resistant or tolerant broccoli cultivars are available. Repeated applications may be required, depending on weather. Use at 7-10 day intervals. Do not apply within this many days of harvest. The Regents of the University of California.