Botrytis rot or gray mold is caused by the necrotrophic fungus Botrytis cinerea. It infects and kills host tissue and extracts nutrients from the dead cells.
Botrytis cinerea affects a wide range of plants including many fruit and vegetable crops. It is economically important on soft fruits such as strawberries. It causes severe pre-harvest losses primarily due to infections of fruit and flowers, especially under humid conditions when daytime temperatures are moderate to warm. Botrytis is also a post-harvest disease because it also grows at refrigerated temperatures.
In greenhouse horticulture, Botrytis cinerea is also known to cause considerable damage in tomatoes; affecting stems, flowers and fruits.