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 Why It’s a Problem. Yams are important to Pacific Island people not only as a staple food but also in
aspects of the cultural and spiritual lives of many islanders. Yam anthracnose is caused by the fungus Glomerella cingulata, also known
as Colletotrichum gloeosporioides. It is a limiting factor for yam production worldwide through its ability to infect leaves and vines, causing
necrosis (death of plant tissue) and dieback of the plant, which, through reduced photosynthesis, leads to under-sized tubers.
Spread of the Disease.
Glomerella cingulata attacks many tropical plant species,
so eliminating the sources of infection is practically impossible, but
because it reproduces in dead plant material, it is advisable to remove the
old yam vines and burn them between seasons.
In our area yam anthracnose particularly
attacks Dioscorea alata, which is the favoured species of yam in six
countries of the Pacific; Federated States of Micronesia, Fiji Islands,
Papua New Guinea, Solomon Islands, Tonga, and Vanuatu. The disease appears to have intensified in recent years for a number
of countries. In the Caribbean infected planting material (tubers) is a major means of spread
of the disease and this is likely to be the case in the Pacific though it has
yet to be proven. Within a crop the fungal spores are spread by rain-splash.
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