VG04013 White Blister – Race ID

The causal organism of white blister is Albugo candida and has been classified into 17 distinct races.

The first 11 are the most important for vegetable production and the remaining 6 are found on mustards.

However, under glasshouse conditions, when plants are at the seedling stage, spores from one host may infect another host.

Scientists have used this behaviour to distinguish between races of white blister and provide insights into the possible origin of the disease in Australia.

Studies on white blister disease in Australian B.olearacea crops showed that:

• The disease does not affect cabbage, although it does in Europe.
• Spores from white blister on Shepherds purse (Ac4) and from Chinese cabbage (Ac7) do not cause white blister on broccoli.
• White blister on broccoli in Australia (Ac9) differs from that found on this crop in Europe as it does not form white blisters on cabbage and does cause white blisters on black mustard.