Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Citrus canker (091)

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  • Widespread distribution. On citrus including grapefruit, kumquat, lemon, lime, mandarin, orange, pomelo and tangerine, as well as other genera in the citrus family. An important disease.
  • Bacterial spots on both sides of leaves and fruit causing them to fall early. Fruit unsightly. Spots up to 10 mm, with haloes on the leaves. Cankers cause twig dieback.
  • Worse on grapefruit, lemon, lime and sweet orange.
  • Spreads in wind-driven rain, water splash, and nursery plants. Enters through natural openings, wounds (e.g., leafminers). Survival is in leaf litter, and weeds.
  • Cultural control: ensure nursery is canker-free; keep out of orchard when leaves wet; plant windbreaks around and between rows; Valencia orange and mandarin tolerant.
  • Chemical control: 2-3 copper fungicide sprays 3 weeks apart, beginning when fruits are about 5 mm diameter.
Common Name

Citrus bacterial canker

Scientific Name

Xanthomonas citri (also known as Xanthomonas citri pv. citri, and Xanthomonas citri subsp. citri).

AUTHORS Helen Tsatsia & Grahame Jackson
Information from CABI (2020) Xanthomonas citri (citrus canker). Crop Protection Compendium. (; Citrus canker (2020) Department of Agriculture, Water and the Environment. (; Citrus canker (2019). Business Queensland. Queensland Government. (; and Plant Biosecurity and Product Integrity (2017) Citrus canker. Department of Primary Industries. NSW. Australia; and from Citrus canker (2019) Agriculture and Food. Department of Primary Industries and Regional Development. Government of Western Australia. ( Photo 2 Kohler F, et al. (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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