How to Manage Colletotrichum in Cyclamen
Colletotrichum is a fungal disease that can infect a large number of cyclamen plants. Under favorable conditions, the disease spreads rapidly. Colletotrichum spreads via water, splash irrigation, direct contact, and contaminated materials. The fungus develops especially under high relative humidity and wet conditions.
How to Recognize Colletotrichum
Colletotrichum on cyclamen can affect leaves, petals, and the crown of the plant. Infections cause leaf spots, stem rot, and heart rot in severe conditions. This can result in reduced plant quality or complete plant losses with serious infections in cyclamen production.
Colletotrichum can affect both young and mature Cyclamen persicum plants. It all depends on the species involved. Because symptoms may initially be subtle, infections can spread unnoticed within a crop before visible damage becomes apparent.
Colletotrichum Species Affecting Cyclamen
The most important Colletotrichum species affecting cyclamen are:
Colletotrichum gloeosporioides (The most common species)
This occurs most frequently and mainly infects young plants and seedlings. It primarily affects young leaves and spreads rapidly, usually causing quality loss rather than immediate plant death.
Colletotrichum cyclaminus (Causes crown rot that can lead to plant loss)
This is less common but more dangerous. It infects mature plants and the crown. Although this fungus spreads more slowly, it can cause heart rot, leading to collapse and loss of the entire plant.
Colletotrichum acutatum (Less frequent and less specialized)
This can also infect Cyclamen persicum, but it is less specialized and occurs less frequently. Infections are generally less severe and often limited to leaf spots and stem lesions.
Colletotrichum Symptoms in Cyclamen
Colletotrichum symptoms in cyclamen include:
Leaves
Small, round to oval brown spots appear on the leaves. Over time, these spots become dark brown or black and may show a glassy margin. Under heavy infection pressure, spots can merge, causing leaves to dry out or fall off.
Petioles
Sunken brown or black lesions develop on petioles. Stems may weaken or break, especially in infections caused by Colletotrichum cyclaminus.
Crown/Heart of the plant
In the case of Colletotrichum cyclaminus, the central crown can become soft, brown, and water-soaked. This leads to heart rot and may result in complete plant loss.
Sporulation
Under humid conditions, black dots appear on leaves and petioles. These structures contain conidia that can infect other plants and accelerate disease spread.
For additional information on Colletotrichum‘s effect on cyclamen and how to prevent it, including favorable conditions that promote Colletotrichum development and its methods of transmission, please read the full report on the Schoneveld Breeding website.
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