Control can also be achieved with the use of fungicides applied when new growth is emerging or as soon as symptoms are visible. Among the compounds registered for use in Connecticut are benomyl and thiophanate-methyl. Consult the label for dosage rates and safety precautions. Stem rot, Sclerotinia sclerotiorum. Symptoms are similar to those of Botrytis blight but sclerotia are large and black and are found in the center of diseased stems.
Control is the same as for gray mold blight.
Leaf blotch, Cladosporium paeoniae. After blooming, purple blotches may appear on the leaves which in wet weather are covered with an olive-grey mold. Destruction of old plant parts in the fall is usually sufficient for control. Symptoms include spots of varied color and size which develop on the leaves. Control can be achieved by removal of plant debris in the fall.