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Pacific Pests, Pathogens & Weeds - Mini Fact Sheet Edition

Giant taro leaf spot (188)

Photo 1. Large number of small round leaf spots, Mycosphaerella alocasiae, up to 8 mm diameter,

Photo 2. Large number of small round leaf spots, Mycosphaerella alocasiae, up to 8 mm diameter,

Photo 3. Spots on leaf of giant taro, Mycosphaerella alocasiae, showing spots of difference sizes, up to 8 mm diameter, with grey centres and brown borders.

Photo 4. Spots on leaf of giant taro, Mycosphaerella alocasiae. Note that the margin of the leaf are first to be infected, and that one side of the leaf is infected first because of the way the leaf unfurls.

Summary

Narrow distribution. South and Southeast Asia, Oceania. On giant taro.A minor disease.
Infection when leaves young, but spots develop later when leaves mature. Spots, grey, sunken with raised brown borders, sometimes with yellow halos.
Sacs containing spores seen in the spots on the top surface of leaves. Sacs burst and spores spread in wind and rain.
Cultural control: none; not likely to impact on corm yield.
Chemical control: none recommended.

Common Name

Giant taro leaf spot

Scientific Name

Mycosphaerella alocasiae; the asexual name is Pasalora colocasiae.

AUTHOR Grahame Jackson & Eric McKenzie
Photo 2 (taken by Eric McKenzie), and used in this fact sheet, appeared previously in McKenzie E (2013) Mycospheaella alocasiae PaDIL - (https://www.padil.gov.au). Photo 3 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. Photo 4 Fred Brooks, University of Hawaii, Bugwood.org.

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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