Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens & Weeds

Eggplant leaf spot (147)


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Common Name

Eggplant leaf spot

Scientific Name

Pseudocercospora egenula

Distribution

It is recorded from Fiji, New Caledonia, Samoa, Tonga, and Wallis & Futuna. Note, Cercospora melongenae is present in American Samoa.

Hosts

Eggplant

Symptoms & Life Cycle

The leaf spots start as small round yellow flecks, which are slightly sunken. As the spots grow larger, their shape becomes more irregular, and they are surrounded by a yellow halo (Photos 1-3). The spots merge and turn brown, and the older leaves die prematurely. Fruits are rarely infected (Photo 4).

The spores of the fungus are produced on the underside of the leaf. They are spread by wind and rain splash.

Impact

This is a wet weather fungus, with leaf spots occurring during the rainy season, November to April. The damage to the plant is relatively slight, and there are differences between varieties. The disease is not so severe that it needs control measures.

Detection & inspection

Look for the slightly sunken irregular spots on the top surface of the leaf, surrounded by yellow haloes at first, which later merge as the leaf ages.

Management

This disease is rarely so severe that it needs control measures.

RESISTANT VARIETIES
If control measures are required, test different varieties of eggplant as some are more tolerant of the disease than others.

CHEMICAL CONTROL
If fungicides were needed to control this disease, then use mancozeb, copper formulations or chlorothalonil.

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When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
Recommendations will vary with the crop and system of cultivation. Expert advice on the most appropriate pesticide to use should always be sought from local agricultural authorities.


AUTHOR 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; and McKenzie EHC (1996) Fungi, bacteria and pathogenic algae on plants in American Samoa. Technical Paper No. 206, South Pacific Commission, New Caledonia; and from (including Photos 12&4) frm McKenzie E (2013) Pseudocercospora egenula: 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.

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