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Pacific Pests, Pathogens & Weeds - Mini Fact Sheet Edition

Algal leaf spot (148)

Photo 1. Algal leaf spots, Cephaleuros virescens, on avocado leaves.

Photo 2. Close-up of algal leaf spots, Cephaleuros virescens, showing the stalks which have spores at their tips. The spores are spread in wind and rain.

Summary

Worldwide in sub-tropics and tropics. On many fruit trees, palms and spice crops. A minor disease in areas of high temperature and rainfall.
Spots green to orange, (sometimes black) 2-4 mm, flattened, with furry growth, and indistinct margins, sometimes resulting in leaf fall and shoot dieback.
Worse with poor nutrition, poor drainage, too much or too little shade.
Cultural control: prune low-hanging branches; check growing conditions – drainage, nutrition, shade, adjust tree density to allow air movement, weed.
Chemical control: no recommendations.

Common Name

Algal leaf spots, red rust (tea and coffee)

Scientific Name

Cephaleuros virescens, Cephaleuros minimus, Cephaleuros parasiticus

AUTHORS Helen Tsatsia & Grahame Jackson
Information from Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany. Photos 1&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.

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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