Photo 1. The dry white crumbly rot at the bottom of the corm is caused by Pythium splendens. The pinkish tissues above and slightly to the right are a reaction to infection by the corm tissues. The white semi-circle on the left is the cottony growth of Athelia rofsii.
Photo 2. Light brown firm rot caused by Phytophthora colocasiae. The rot on the lower left side is caused by Athelia rolfsii. The corm has been incubated at high humidity overnight to stimulate the growth of the fungus.
Photo 4. Black spongy rot caused by Lasiodiplodia theobromae. These rots usually follow those of Pythium and Phytophthora, or they come in later after the corms have started to lose moisture.
Taro corm rots (post-harvest)
The following are the commonly recorded rots that develop in taro corms after harvest:
Athelia rolfsii (see Fact Sheet no. 11)
Lasiodiplodia (Botryodiplodia) theobromae
Phytophthora colocasiae (see Fact Sheet no. 14)
Erwinia species: Erwinia carotovora subsp. carotovora (see Fact Sheet nos. 101, 214, 296), and Erwinia crysanthemi.
AUTHOR Grahame Jackson
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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