Informational table showing disease name, symptoms, pathogen/cause, and management of Cyclamen diseases. Disease Symptoms Pathogen/Cause Management 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 a fungicide 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 Spot 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 a fungicide to protect healthy 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.

Fusarium wilt.

Ringspots

Impatiens necrotic spot virus symptoms on leaves and flowers (Photos by F. E. Gildow, Penn State)

Prepared by Gary W. Moorman, Professor of Plant Pathology