Prepared by Maher Jabado

Botrytis Funghus disease (Gray mold)

Gray mold (Botrytis) — This fungus attacks senescing plant tissue such as the petals of flowering ornamentals such as African violet, begonia, hydrangea, chrysanthemum, exacum, geranium, impatiens, marigold, poinsettia, snapdragon, flowering ornamentals particularly during periods of high humidity and little air movement. Leaves often become infected where petals have fallen on the leaf tissue. It is the most common foliage disease on greenhouse grown crops and is difficult to control without careful monitoring and management of the environmental conditions in the greenhouse. Lesions on infected plants produce a multitude of spores giving the disease its common name ‘gray mold.’ The spores are liberated by air currents, watering, or any worker-associated activity such as disbudding, pruning, or spraying pesticides. Fenhexamid, chlorothalonil and strobilurin fungicides provide some prevention of disease but fungicide resistance is common to thiophanate-methyl and dicarboximide based fungicides

Chlorothalonil (Concorde, Daconil Ultrex, Echo 720, Termil, 2787) — chloronitrile: This product is one of the most widely used fungicides in this industry. It is used as foliar spray, a soil drench, and as a greenhouse fumigant/smoke in the greenhouse industry (Termil). The product is labeled on numerous crops and has long standing grower acceptance and is valuable in pesticide resistance management of fungal leaf spots, powdery mildew, rust and Botrytis diseases.