Photo 1. White rust (or white blisher rust), Albugo ipomoeae-aquaticae, on the underside of kangkong, Ipomoea aquatica.
Photo 2. Blisters of cabbage white rust, Albugo candida, on the outer leaves of Chinese cabbage (especially top right and bottom left).
Photo 3. Pustules of white blister rust, Albugo candida, on the underside of a Chinese cabbage leaf. The pustules have burst and are releasing the powdery spores. On the upper surface the spots are yellow-green.
Photo 4. Pustules of white blister rust, Albugo candida, on the underside of radish leaves. The pustules are round at first, smooth, white and shiny. Later, they are powdery after they have burst to release the spores. Severe infection causes leaves to become distorted and to die early.
Photo 7. Close-up (Photo 6), white blister rust , Albugo species, on Ipomoea aquatica (Tonga), showing merging blisters containing the sporangia.
White rust, white blister
Albugo candida. There are different strains. Other species are present in Pacific island countries, for instance, Albugo ipomoeae-aquatica (Photo 1) and Albugo ipomoeae-panduratae.
AUTHOR Grahame Jackson
Information (and Photos 1&4) from Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, Tony Cooke, Susan House. CSIRO Publishing; and from Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany. Photos 2&3 Kohler F, Pellegrin F, Jackson G, McKenzie E (1997) Diseases of cultivated crops in Pacific Island countries. South Pacific Commission. Pirie Printers Pty Limited, Canberra, Australia. Photo 5 Jacquie (Wright) Kami, formerly Plant Pathologist, Secretariat of the Pacific Community, Suva, Fiji. Photos 6&7 Mani Mua, SPC, Sigatoka Research Station, Fiji. Diagram Eric McKenzie (2013) Albugo candida. PaDIL - (http://www.padil.gov.au).
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.
This mini fact sheet is a part of the app Pacific Pests and Pathogens
The mobile application is available from the Google Play Store and Apple iTunes.