What causes the raised, white blisters under the leaves?
The disease white blister is caused by the fungus Albugo candida. This disease, which affects mostly cauliflower and brocolli, has recently been found in the Lockyer Valley in Queensland, and has been in New South Wales, Tasmania and Victoria for the last few years. Symptoms of white blister of brassica appear on leaves as yellow brown spots with small raised white blisters or pustules underneath. Swelling may also be found on roots, stems and flowers. The seedlings contain masses of white dusty spores. The disease causes the plant to distort and reduces the marketability of flower heads and the production of seeds.
