|Anthracnose and Crown Rot||Young plants wilt, yellow and die. Tan to brown spots with yellow halos develop on flower stalks, wings, and flower parts. These enlarge, become reddish brown to brown or black on some cultivars.||Colletotrichum gloeosporiodes||Apply a fungicide to protect plants.|
|Bacterial Rot||Yellow and dead leaves are found among healthy basal rosette leaves. Symptoms sometimes develop only on one side of the mid-vein. Veins may be red. Crowns and entire plant die. Rotting crowns smell foul.||Pseudomonas||Plant disease-free seedlings.|
|Botrytis Blight||Leaves on seedlings die and become covered with gray mold. Flowers discolor and collapse. When dried, infected flowers fall out of the head. Entire flower stalk may yellow and die.||Botrytis cinerea||Purchase decorticated seed that has been treated with hot water and fungicide. Avoid overhead irrigation. Water early in the day so that leaf surfaces dry. Space rows and maintain good weed control to insure adequate air circulation. Apply a fungicide to protect plants.|
|Cercospora Blight||Small reddish spots form on leaves and flower stalks. Spots become brown and the entire leaf dies.||Cercospora insulana||Apply a fungicide to protect plants.|
|Red Leaf||Leaves redden.||Cold weather or virus infection.||Cold weather-injured plants recover. Virus-infected plants do not recover and should be destroyed.|
|Rhizoctonia Crown Rot||Gray spots develop on leaves near the soil. The crown and entire plant die.||Rhizoctonia solani||Apply a fungicide to protect plants.|
|Seedling Blight||Seedlings are killed.||Alternaria, Botrytis, Stemphylium, Fusarium, Cercospora, and Colletotrichum.||Produce seedlings from decorticated, hot water and fungicide-treated seeds.|
|Virus||Depending upon virus involved, stunting, deformed leaves, mosaic, red leaves, red or yellow line patterns and ring spots may develop.||Broadbean wilt, cucumber mosaic, statice Y, tobacco rattle, tomato bushy stunt or turnip mosaic virus.||Destroy infected plants. Maintain good aphid control to delay virus spread. Wash hands and disinfest tools thoroughly after handling infected plants to prevent mechanical spread.|
|Yellows||Small leaves, yellowing, stunting, and excessive branching occur. Mature plant leaves may redden. Flowers may fail to open, be reduced in size, or have abnormal color and shape.||Phytoplasma||Destroy infected plants. Maintain good leafhopper control to delay spread.|
Prepared by Gary W. Moorman, Professor of Plant Pathology
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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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