Botrytis Grey Mould

Symptoms & Conditions for disease development

Botrytis is favoured by very humid conditions created where plants are growing closely together or in glasshouses or chambers where there is no air circulation. The lower leaves and stem bases are mostly affected and show a brown leaf spotting and tip burn from which arises a fluffy mycelium later followed by a mass of grey spores.

Botrytis grey mould on flowers © Szczepan Marczynski

Botrytis grey mould on leaves © Szczepan Marczynski

Control Methods

Avoid conditions that are favourable for the disease. Apply fungicides which specifically target Botrytis as general purpose fungicides are not effective against this disease.

Products containing the following active ingredients which are effective against the disease can be separated into four chemical classes:

1. cyprodinil and pyrimethanil
2. fludioxonil
3. procimidone and iprodione
4. fenhexamid

Botrytis can become resistant to individual fungicides and products from different chemical classes should be rotated.

Text ©2007 Paul Margot