Botrytis cinerea

(Grey mould or gray mold)

• Causal agent and transmission

Grey mould caused by the fungus Botrytis cinerea is a very common disease on many plants. In general, it is not a serious problem for potatoes except in cold  (average of 10 ° C) and humid (especially foggy) climates. The foliage of maturing crops may be partially or totally destroyed by this fungus, but usually without a significant impact on production.

Botrytis cinerea is a necrotrophic polyphagous fungus belonging to the Ascomycota division and the Sclerotiniaceae family. It is highly polyphagous and it is able to cause the grey mould disease on several hundreds of plant species. The damage is usually very limited on potato but on other crops, it may cause significant damage, both in open field or under glasshouses, causing stems cankers as well as losses associated with rotting tissue, especially on fruits.The resulting losses on fruit are important worldwide notably on economically important crops such as tomato, strawberry or grapevine.

• Significance

Grey mould caused by Botrytis cinerea is present all over the world on the potatoes, but the damage is usually not significant on this crop. However, in areas with a long growing season, low temperatures, long periods of wetting the leaves and a lack of light, grey mould can be a very harmful disease. Such conditions exist in regions where potatoes are grown at high altitude and in tropical and subtropical areas, when potatoes are grown at low altitude in very short days with a formation of thick fog.

Chemical treatment usually controls this problem, whose economic impact is quite rare in potato crops.