| 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 azoxystrobin,
chlorothalonil, copper, fludioxonil, iprodione 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 chlorothalonil or fludioxonil to protect
plants. |
| Pythium Root Rot |
Young plants die. Stunting and root
rot occur on older plants. |
Pythium
sp. |
Plant in pasteurized media. Keep
hose ends off the ground. Discard infected plants. Apply etridiazole
to protect healthy 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.
Concentric line patterns may form on leaves. |
Impatiens necrotic spot, tobacco
mosaic, cucumber mosaic, tobacco rattle, tomato aspermy, potato
virus X |
Discard infected plants. Maintain
good aphid and thrips control. Wash hands thoroughly and frequently
when handling plants to prevent mechanical spread. |
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