Gray mold of crocus

The causal agent of this fungal disease is Botrytis croci, a pathogen that poses a significant threat to crocus cultivation. As an infectious fungus, it targets the bulbs and foliage of plants within the Crocus genus, often leading to rapid tissue decay and the loss of the entire crop if not managed effectively.

This pathogen specifically attacks the bulbs, causing decay that frequently begins at the basal plate or through wounds sustained during harvesting. Once established, the fungus can progress to the emerging shoots, preventing them from breaking through the soil surface or causing them to rot shortly after emergence.

Signs of infection include discolored brown lesions on the bulb scales, which eventually become covered in a distinctive gray, velvety mycelium and sporulation. In the field, affected plants may show signs of premature yellowing, wilting, and collapse of the leaves. In humid weather, this gray fuzzy growth becomes more prominent on both the bulbs and the base of the stems.

The development of Botrytis croci is strictly linked to moisture levels and temperature. High humidity combined with poorly drained soils or inadequate ventilation during bulb storage creates an ideal environment for the spread of spores. Spores can persist in the soil for several years or travel through the air to contaminate healthy crops.

Effective management requires strict adherence to agricultural hygiene. Growers should prioritize the selection of healthy, unblemished bulbs and ensure that planting sites have excellent soil drainage to prevent waterlogging. Fungicidal treatments applied during the pre-planting phase, along with maintaining low moisture levels in storage facilities, are critical for minimizing the impact of this disease.