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How to Manage Pests

UC Pest Management Guidelines


Blooming cyclamen.

Floriculture and Ornamental Nurseries

Cyclamen (Cyclamen spp.)

Disease Control Outlines

(Reviewed 3/09, updated 3/09)

In this Guideline:


Disease (causal agent) Symptoms Survival of pathogen and effect of environment Comments on control
Gray mold (Botrytis cinerea) 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 info *
Soft rot (Erwinia chrysanthemi) 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.
Root rot (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 wilt (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 *
Leaf spots (Phyllosticta cyclaminis) 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.
(Cryptocline [=Gloeosporium] cyclaminis) Distinctly zonate, pale green and circular spots. Orange to pink-colored spores on stems and leaves.    
(Septoria cyclaminis) Red concentric spots turn gray with red borders.
Stunt (Ramularia cyclamanicola) 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.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries
UC ANR Publication 3392
Diseases
S. T. Koike, UC Cooperative Extension Monterey County
C. A. Wilen, UC IPM Program, UC Cooperative Extension San Diego County
Acknowledgment for contributions to Diseases:
R. D. Raabe, (emeritus) Environmental Science, Policy, and Management (ESPM), UC Berkeley
A. H. McCain, (emeritus) Environmental Science, Policy, and Management (ESPM), UC Berkeley
M. E. Grebus, Plant Pathology, UC Riverside

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