Photo 1. Spots - blister or craters - caused by citrus canker, Xanthomonas citri. Note the spots are surrounded by a yellow halo or margin, and that the leaves are not distorted as they are by citrus scab, Elsinoë fawcettii.
Photo 2. Close-up of the pustules formed by citrus canker, Xanthomonas citri, showing yellow haloes.
Photo 4. Underside of the leaf in Photo 3, showing pustules of citrus canker, Xanthomonas citri, without haloes. (Note the dark margins to the spots is not typical of scab, Elsinoë fawcettii).
Photo 5. Raised pustules on the surface of a lemon, caused by citrus canker, Xanthomonas citri, without yellow haloes.
Citrus bacterial canker
Xanthomonas citri (also known as Xanthomonas citri pv. citri, and Xanthomonas citri subsp. citri).
AUTHORS Helen Tsatsia & Grahame Jackson
Photo 2 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. Photos 3-5 Richard Markham, ACIAR, Canberra.
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.
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