The wilt will intensify and leaves yellow, often taking on a scorched appearance. Typically, initial wilting will occur in warm weather, followed by partial recovery in the evening. Peonies like good drainage and overly wet soil can result in rots or wilts. See “ Crown Rot of Perennials (Southern Blight).” The problem generally requires removal of the diseased plant. Enough sclerotia may form to create a crust on the soil. Sclerotia, which resemble mustard seeds and vary from white to reddish tan to light brown in color, develop at the base of the plant. During periods of high humidity, coarse cottony webbing (mycelia) develops and fans out over the stem base and surrounding soil. Beginning in early summer, infected plants develop discolored, water-soaked stem lesions near the soil line. Southern blight, a fungal disease, causes deterioration and rotting of the tissues at the crown of the plant causing the leaves to turn yellow, collapse, and die. Southern blight (also called, crown rot or white mold) Sclerotia (resembling mustard seeds) and white cottony webbing on anemone Sclerotinia rot of peony VA Tech Learning Resource Center, VPISU, See “ Phytophthora Root Rot of Trees and Shrubs.” Lookalikes: Botrytis blight (has fuzzy, gray mold) and other rots and wilts The entire plant can be pulled up easily. The plant can develop root and crown rot causing the entire plant to rot. The stems around the soil-line may appear darkened and leathery they may wilt and die. Flooded and saturated soil conditions are especially conducive to the spread of phytophthora blight. See “ Fungal spots, blights, and blotches.”ĭepartment of Plant Pathology Archive, NCSU, Ī fungus, Phytophthora cactorum, which lives in moist soils, causes phytophthora blight. Lookalikes: Anthracnose diseases (many are also leaf spots) and scorch (symptoms are browning of leaf margins and/or yellowing or darkening of the areas between the main leaf veins) In most cases, fungal leaf spot diseases are not significant enough to warrant fungicide applications. When the spots become numerous and begin to merge the disease is called a blight or blotch or less commonly, scorch. Leaf spots are typically tan to brown with distinct borders or delimited borders on leaves or flower parts. Most fungal leaf spots cause only cosmetic damage or occur late in the season, thus do not warrant control. Peonies can be affected by a variety of fungal leaf spots. The disease is considered more unsightly than harmful. Powdery mildew is a fungal disease producing a light gray or whitish powder on the surface of leaves, young stems, and flowers. Lookalikes: Botrytis blight (has fuzzy, gray mold) It does not cause early leaf drop or stem dieback but causes the plant to be unsightly and lose its attractiveness as spots coalesce to form blighted areas. Eventually the whole plant may have purplish or brownish red spots.Īlthough not immediately lethal, repeated bouts for several years will affect plant vitality.

Short reddish-brown streaks appear on the young stems and petioles. Later they coalesce intolarge, glossy, irregular dark purple blotches, while the underside of the spots becomes a dull chestnut brown. Small, circular red or purplish spots first appear superficially on the upper surface of young leaves. This fungal disease occurs in spring just before blooming and affects all above ground parts. Peony blotch (also called red spot or measles) Lookalikes: Blights (such as, phytophthora blight, which lacks the classic fuzzy, gray mold), leaf spots, bud blast. Open flowers are occasionally affected and may turn brown and develop a covering of gray mold. Small buds that are affected turn black and wither. Just above ground level, the stalk becomes covered with gray mold, which sheds large numbers of spores. The rotted portion of the plant becomes covered with a soft brown or blackish mass of fungal spores. Stems often have a water-soaked appearance. Young shoots rot at ground level when they are 5 to 8 inches tall. Botrytis blight is the most common disease of garden peonies and is prevalent in damp, rainy seasons.

Southern blight treatment