Brown or gray fuzziness on lower leaves can signal the onset of this fungal disease.
Published January 08, 2024
Botrytis blight on marigold
Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org
Botrytis blight, also know as gray mold, is a fungal disease caused by several species in the genus Botrytis. It affects the buds, flowers, leaves and bulbs of many nursery and greenhouse crops. Wounded or weakened plants are particularly susceptible to this disease. The responsible fungi spreads quickly in periods of high humidity or when there is moisture on plant tissue. It can survive year-round in greenhouses due to the relative humidity. Nurseries should be extra vigilant during rainy and drizzly weather conditions.
Source: Missouri Botanical Garden, Michigan State University Extension