|Bacterial blight||Spotting may be accompanied by rings of dark red pigment or sometimes yellow haloes.||Xanthomonas||Maintain good air circulation. Promptly remove and destroy plant debris at season end. Avoid overhead irrigation.|
|Botrytis blight||Young shoots discolor, wilt, and fall over. Later, browned buds and blighted leaves may develop masses of gray, fuzzy fungal spores.||Botrytis cinerea or Botrytis paeoniae||Avoid overhead irrigation. Maintain low humidity. Remove infected plant parts. Clean up debris at season end. Apply mancozeb, manganese + zinc, copper salts, or copper hydroxide.|
|Crown gall||Galls or overgrowth of tissue form at the soil line or along the stems||Agrobacterium tumefaciens||Remove infected plants and surrounding soil. Avoid wounding plants at or near the soil line.|
|Leaf blotch or measles||Small, reddish spots that can coalesce to form large, irregular purple blotches on leaves and stems. Lesions are also formed on stems.||Cladosporium paeoniae||Avoid overhead irrigation. Maintain low humidity. Remove infected plant parts. Clean up debris at season end. Apply propiconazole or manganese + zinc.|
|Nematodes||Plants are stunted and yellowed. Small galls occur on roots or roots have little branching||Meloidogyne, Rotylenchus, Ditylenchus||Remove infected plants and do not replant there for one year. Till the soil to keep it weed free for one year before replanting.|
|Phytophthora blight||Infected parts become dark brown to black and somewhat leathery, and shoots may die. Crowns may also develop a dark, wet rot.||Phytophthora||Avoid planting in wet or poorly drained areas. Remove and destroy infected plants.|
|Powdery mildew||Foliage becomes coated with white mycelium.||Erysiphe||When mildew is observed, apply propiconazole, mancozeb, manganese + zinc, copper salts, or copper hydroxide.|
|Root rot||Plants are stunted, yellowed, wilt, and die.||Fusarium, Rhizoctonia, or Thielaviopsis||Remove infected plants.|
|Southern blight||Stems turn water-soaked at the base, then wilt. The base of diseased stems will often show fans of thick, ropy-textured fungal mycelium and numerous, tiny, spherical sclerotia that turn from white to brick red as they mature.||Sclerotium rolfsii||Destroy infected plants.|
|Verticillium wilt||Wilting of shoots in the absence of damage to the crown.||Verticillium albo-atrum, V. dahliae||Remove and destroy infected plants, and do not replant peonies.|
|Viruses,||Ringspots, light and dark green mottling on the leaves, stunting, curled leaves, and poor growth.||Tobacco rattle, Tomato spotted wilt, Alfalfa mosaic viruses||No treatment is recommended if plants are only mottle but are growing well. Stunted plants and those not growing well should be removed.|
|White mold||Can cause stem rot on peony. The entire plant may wilt, or only a portion of it. Infected areas of the stem turn a light tan color and may become withered and stringy. Under wet conditions, fluffy white fungal growth (mycelium) often appears.||Sclerotinia sclerotiorum||Do not replant in infested areas. Maintain good air circulation.|
Active Ingredients and Trade Names of the Chemicals
Fungicides and Fungicide Resistance Management - Certain fungicides are said to be ‘at risk’ to the development of resistance if they are used repeatedly. 1 = low risk; 2 = moderate risk; 3 = high risk. Fungicide Resistance Action Committees (FRAC) have developed a numbering system in which chemicals with the same FRAC Group number have the same mode of action. That is, chemicals with the same FRAC number kill the fungus in the same way (See http://www.frac.info/frac/index.htm). If a fungus has resistance to a chemical with a particular FRAC number, it is most likely resistant to all the other chemicals with that same number. It is recommended that chemicals at high risk be used sparingly and in rotation or mixed with chemicals with different modes of actions (different FRAC number).
|FRAC Group||Risk||Class of fungicide||Active ingredient||REI Restricted Entry Interval (hrs)||Trade names (EPA reg. no.)|
|M||1||copper, complex||copper sulfate||12, 24||Camelot (1812-381)|
|Copper fixed||copper hydroxide||48||CuPRO (67690-37)|
|cupric hydroxide||48||Champ (55146-64)|
|Dithio-carbamate||mancozeb||24||Dithane (707-180) FORE (707-87) Pentathlon (1818-251)|
|manganese + zinc||24||Wingman (81943-22)|
NOTICE: THE USER OF THIS INFORMATION ASSUMES ALL RISKS FOR PERSONAL INJURY OR PROPERTY DAMAGE. WARNING! PESTICIDES ARE POISONOUS. READ AND FOLLOW ALL DIRECTIONS AND SAFETY PRECAUTIONS ON LABELS. HANDLE CAREFULLY AND STORE IN ORIGINAL LABELED CONTAINERS OUT OF THE REACH OF CHILDREN, PETS, AND LIVESTOCK. DISPOSE OF EMPTY CONTAINERS RIGHT AWAY, IN A SAFE MANNER AND PLACE. DO NOT CONTAMINATE FORAGE, STREAMS OR PONDS.
Issued in furtherance of Cooperative Extension work, Acts of Congress, May 8 and June 30, 1914, in cooperation with the U. S. Department of Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.
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