Narcissus leaf scorch

Narcissus leaf scorch, caused by the fungus Stagonospora curtisii, is a destructive disease affecting various bulbous plants. It is commonly identified by the reddish-brown lesions that appear on the foliage and the neck of the bulb, often referred to as red bulb disease.

While primarily affecting Narcissus species, the pathogen is also known to infect Amaryllis, Hippeastrum, and Crinum. The fungus is persistent and can remain viable in infected plant debris or within the bulb scales during the dormant season.

Initial symptoms include small, reddish spots on the leaf tips, which expand into larger, elongated lesions. As the infection progresses, the leaves wither and die prematurely. On the bulbs, the disease manifests as irregular red or brown patches, which can penetrate deep into the bulb tissue.

The development of the disease is heavily favored by cool, wet weather and high humidity. Splashing water from rain or irrigation facilitates the spread of fungal spores from the soil to the leaves. Overcrowded planting conditions further exacerbate the severity of the outbreak.

Effective management and prevention strategies include:

• Selecting only healthy, disease-free bulbs for planting.
• Improving air circulation and drainage to reduce surface moisture.
• Removing and destroying all infected plant materials after the growing season.
• Treating bulbs with appropriate fungicides before planting and applying foliar sprays during early growth.