Gary W. Moorman, Professor of Plant Pathology
|BACTERIAL SOFT ROT||Yellowing plants wilt and die rapidly. Corms have a wet, soft rot.||Erwinia carotovora or Erwinia chrysanthemi||Plant only healthy, sound corms. Discard infected plants. Plant in pasteurized media.|
|BOTRYTIS BLIGHT||Leaf spots become tan in color. Flower petal spots are at first water-soaked but become tan. Infected crowns, petioles, and developing flowers are covered with gray fungal growth.||Botrytis cinerea||Reduce the humidity in the greenhouse. Space plants to insure good air circulation. Apply chlorothalonil, iprodione, azoxystrobin, or fludioxonil to protect healthy plants.|
|FUSARIUM WILT||Infected plants become very yellow. Vascular tissue in the corm turns dark brown to black. Mature plants wilt and die.||Fusarium oxysporum f. sp. cyclaminis||Plant sound, disease-free corms in pasteurized media. Discard infected plants.|
|LEAF SPOTS||Yellow or brown or gray circular spots develop on leaves and may have a zonate pattern within them. Small dark brown dots can be seen within the spots.||Septoria, Gloeosporium, or Phyllosticta||Water plants in a manner that does not wet the leaves. Apply thiophanate methyl or chlorothalonil to protect plants.|
|PYTHIUM ROOT ROT||Young plants die. Stunting and root rot occurs on older plants.||Pythium||Plant in pasteurized media. Keep hose ends off the ground. Discard infected plants.|
|THIELAVIOPSIS ROOT ROT||Stunted plants have blackened roots.||Thielaviopsis basicola||Plant in pasteurized media. Discard infected plants.|
|VIRUSES||Flowers may be abnormal in shape. Leaves are deformed and streaked with yellow or brown markings or have ringspots in a thumb-print like pattern.||Tobacco mosaic, cucumber mosaic, tobacco rattle, tomato aspermy, potato virus X, impatiens necrotic spot||Discard infected plants. Maintain good aphid and thrips control. Wash hands thoroughly and frequently when handling plants to prevent mechanical spread.|
Impatiens necrotic spot virus symptoms on leaves and flowers (Photos by F. E. Gildow, Penn State)
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.)|
|1||3||Benzimidazole||thiophanate methyl||12||3336 (1001-69), OHP 6672 (51036-329-59807), Fungo Flo (51036-329-59807), Systec 1998 (48234-12)|
|2||3||Dicarboximide||iprodione||12||Chipco 26GT (100-1138), Chipco 26019 (264-481), Iprodione (51036-361), Sextant (51036-361-59807)|
|M||1||Chloronitrile||chlorothalonil||48||Daconil (50534-9), Exotherm Termil (70-223)|
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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