← All pests and diseases

Black rot of cabbage

Disease Xanthomonas campestris

Spots or blotches on leavesYellow, curled, or mottled leaves

A cabbage leaf with a yellow patch of black rot at the edge
Photo: Scot Nelson, Wikimedia Commons (CC0)

How to spot it

Yellow V-shaped patches at leaf edges, pointing toward the middle of the leaf, with black veins inside.

What it does

Leaves brown and drop, and heads can rot.

What to do now

  • Pull and throw away infected plants.
  • Stay out of the planting while it's wet.

Keep it away next time

  • Buy seed that's been hot-water treated, or certified disease-free.
  • Keep cabbage-family crops out of that spot for 3 years.
  • Control mustard-family weeds.

Plants it affects

Every plant in the cabbage family (brassicas).

Not sure? Your county extension office can identify it from a photo or sample, often for free.