|Disease (causal agent)
||Survival of pathogen and effect
||Comments on control
||Spotting of flowers. Decay of
emerging flower stems and leaf petioles under leaf canopy. Woolly gray fungal spores form on rotted tissues.
||In plant debris, especially
flowers. Common saprophytic fungus. Favored by cool, wet weather. Water necessary for spore germination.
||Avoid overhead watering. Remove
old flowers. Improve air circulation. Control humidity to avoid moisture
condensation. Treat with iprodione or fenhexamid. more
||Plants collapse suddenly. Tuber is mushy.
||Infected plants and debris.
Disease is favored by high temperatures (75°F and above). Bacteria are spread by splashing water and handling.
||Discard infected plants. Avoid
excessive water splashing. Maintain sanitary conditions. Keep greenhouse cool.
(Pythium and Phytophthora spp.)
||Plants are stunted. Roots are discolored and rotten, lower leaves wilt and may turn yellow.
||Pathogens are normal inhabitants of natural soil. Disease is favored by poor drainage and overwatering.
||Heat‑treat growing medium at
140°F for 30 minutes or fumigate. Drench plants with mefenoxam. More info: Pythium Root Rot, Phytophthora Root and Crown Rots *
(Fusarium oxysporum f. sp. cyclaminis)
||A progressive yellowing and
wilting of leaves starts with oldest. Brown discoloration of the vascular tissues in tubers. Tuber remains firm unless secondary bacteria are introduced.
||Survives as resting spores
(chlamydospores) in soil. No other plants are infected. Disease is favored by temperatures above 70°F. May be seedborne.
||Discard infected plants and soil;
don't save seed from infected plants. Good sanitation generally provides
adequate control. Thiophanate-methyl drenches during early growth period
should be helpful. Adjust soil pH to 6.5 to 7.0. Treat seed with a
fungicide. more info *
||Yellowish‑to‑brownish spots near leaf margins.
||On diseased plants and plant debris. Favored by wet conditions. Dissemination of spores is by splashing water.
||Control is same as for gray mold. Protect foliage with a fungicide.
||Distinctly zonate, pale green and circular spots. Orange to pink-colored spores on stems and leaves.
||Red concentric spots turn gray with red borders.
||Conspicuous stunt. Flower
peduncles shortened so that flowers open below surrounding leaves. Reddish
brown necrosis in tuber. Brown irregular leaf spots. Frosty appearance on underside of lower yellowed leaves.
||Infected plants and debris. Spores are airborne. Favored by warm, moist conditions.
||Dispose of infected plants, keep
humidity low. Keep seedlings away from older plants. Protect plants with thiophanate-methyl.
|Cyclamen are also susceptible to black
root rot (Thielaviopsis basicola) and
Cylindrocladiella disease (Cylindrocladiella peruviana).
|* For additional information, see section on Key Diseases.