Gary W. Moorman, Professor of Plant Pathology
|ANTHRACNOSE||Dead spots 1/8 to 1/4 inch with dark brown margins and gray centers form on leaves. Dark concentric lines form within the spots. Sunken brown to tan spots form on stems, girdle them and kill the plant.||Colletotrichum violae-tricoloris||Apply mancozeb or thiophanate methyl + mancozeb.|
|CERCOSPORA LEAF SPOT||Small black, circular spots form on the lower leaves under moist conditions.||Cercospora||Apply myclobutanil, mancozeb, triadimefon, chlorothalonil, or thiophanate methyl + mancozeb during wet weather.|
|FUSARIUM WILT||Plants wilt and die quickly. Roots are rotted.||Fusarium oxysporum||Destroy infected plants.|
|PYTHIUM ROOT ROT||Lower leave yellow as root rot. This is easily confused with Thielaviopsis root rot.||Pythium||Plant in pathogen-free potting mix. Avoid over-watering. Discard flats of infected plants. Fungicides effective for Pythium tend to stunt young pansies. Apply potassium salts of phosphorus acid, thiophanate methyl + etridiazole, mefenoxam, fosetyl-Al or dimethomorph.|
|SCAB||Round spots up to 1/4 inch in diameter which are yellow or cream colored form on any part of the plant. Spots are slightly raised and appear scabby. Infected leaf tissue may fall out leaving holes in the leaf. Stems are girdled and plants die.||Sphaceloma violae||Apply mancozeb, or thiophanate methyl + mancozeb.|
Cercospora leaf spot. Anthracnose.
Active Ingredients and Trade Names of the Chemicals
|FRAC Group No.||Risk Level||Class||Active ingredient||REI Restricted Entry Interval||Trade names (EPA Reg. No.)|
|3||2||Triazole||triadimefon||12||Strike (3125-436), Bayleton (432-1360)|
Fungicides and Fungicide Resistance Management - Certain fungicides, usually systemic fungicides, are said to be 'at risk' to the development of resistance if they are used repeatedly. See the Risk Level in the above table (1 = low risk; 3 = high risk). The Fungicide Resistance Action Committee has developed a numbering system in which chemicals with the same FRAC Group number have the same mode of action (See http://www.frac.info/frac/index.htm ). 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).
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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