Photo 1. Dark brown to black streaks caused by the banana rust, Uredo musae. Often the streaks feel slightly rough due to the spore masses of the fungus.
Banana rust, banana leaf rust
Narrow. Southeast Asia (Malaysia, Indonesia, and the Philippines). In Oceania, it has been recorded from American Samoa, Australia, Fiji, Palau, Papua New Guinea, Samoa, and Solomon Islands.
Banana and plantain varieties.
Dark brown to black streaks appear on the leaves, often surrounded by yellow halos (Photos 1&2). The streaks are more numerous on the lower surface of the leaves. They are slightly raised, and feel rough to the touch due to the spore masses of the fungus. If the disease is severe, the leaves may turn yellow. Mainly the older leaves are affected.
The disease is rarely important. Reports from Samoa (1981) and Philippines (1971) suggest it was serious when only benzimidazole fungicides, e.g., benomyl, were used against black Sigatoka disease. However, benomyl is no longer used, and in many countries registration has been cancelled. For instance, in Australia, it became illegal to supply or use products containing benomyl after December 2006.
Look for the slightly raised "rough" spores masses associated with blackish-brown streaks, especially on the underside of the leaves.
This is only a minor disease, and control measures are not necessary.
In commercial plantings, the rust is controlled by the fungicides that are used for black Sigatoka (see Fact Sheet no. 02). There is evidence that the disease was worse when benomyl was used extensively, and also when oil is used on its own.
AUTHOR Grahame Jackson
Photo 1 Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany. Photo 2 Diseases of fruit crops in Australia (2009). Editors, Tony Cooke, Denis Persley, Susan House. CSIRO Publishing.
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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