Corm Rot
Fusarium oxysporum f. sp. gladioli
A soilborne fungal disease of gladiolus and related corm flowers that rots the corm in the ground and in storage, while yellowing and stunting the plant above. Fusarium corm rot is the most common and serious disease of gladiolus, and because it lingers in the soil and on infected corms it is easily carried from year to year.
🔎 How to spot it
Above ground, plants are stunted with yellowing leaves and may fail to flower. The corm shows dark brown, sunken, often circular rotted areas on the side or top, or a brown decay of the basal plate, and cut open it has brown streaks in the conducting tissue. A firm, dark dry rot frequently develops in stored corms that were not cured or matured properly.
🥀 Damage it causes
The fungus rots the corm and plugs the tissue that moves water, so plants are weak, yellow, and stunted, flower poorly or not at all, and may die. Infected corms break down in storage, spreading the rot to others, so a batch of saved corms can be lost over winter. The disease reduces both the planting stock and the flower display.
🔬 What causes it
Corm rot is caused mainly by Fusarium oxysporum f. sp. gladioli, a soil fungus that survives for years in the soil and on infected corms as tough resting spores. It is favored by warm soil and is spread on contaminated corms, soil, and debris. Corms that are bruised, or dug and stored before they mature and cure, are especially prone to the storage phase of the rot.
🛡️ Prevent it
Start with clean, firm, certified planting stock and inspect every corm before planting, discarding any with lesions, soft spots, or discoloration. Rotate to a fresh planting site, since the fungus builds up in the soil, and avoid warm, wet, poorly drained ground. Dig corms carefully at maturity, cure them quickly and thoroughly, and store them cool, dry, and airy.
🧯 If it is already here
There is no cure for an infected corm; rogue out and destroy stunted, yellow plants and any rotted corms, and never save corms from a diseased planting. Move the next planting to clean ground and rely on sound stock and good curing and storage. Fungicide dips of clean corms before planting can help where the disease is established, but sanitation and clean stock are the foundation.
💡 Good to know
Because the fungus persists in the soil and travels on corms, the two most powerful tools are planting only clean stock and rotating to fresh ground. Thorough curing after digging is what prevents the dry storage rot. The same Fusarium also causes a yellows that stunts and discolors the foliage.
🌱 Plants it affects
7 plants in the library can be affected by this problem
For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.