Botrytis (also known as gray mold) is most often, but not always, associated with greenhouses. It occurs on outdoor plantings following cool, damp, cloudy weather. Dahlias started from cuttings are particularly susceptible to botrytis.

The picture on the right shows botrytis in its initial stage--most often attacking the leaf edges of tender shoots.

The picture on the lower right shows botrytis in the "gray mold" stage. Botrytis often appears on fruit such as strawberries in supermarket produce departments.



Avoid splashing water on the foliage. Free moisture is needed for spore germination and infection.

Remove and destroy affected parts and other plant debris. The fungus readily attacks aging or dead tissue and then produces tremendous quantities of airborne spores.

Provide good air circulation around the plants.

Apply fungicide when symptoms first appear. Use several chemicals on a rotational basis to avoid building resistance of one chemical by the botrytis spores.

Benomyl (Benlate), chlorothalonil (Daconil 2787, Exothherm Termil), iprodione (Chipco 26019) and vinclozolin (Ornalin) are fungicides widely recommended for botrytis control.


Home Go to Disease Index Go to Dahlia Culture