Dry rot of gladiolus

Dry rot of gladiolus is a severe fungal disease caused by the pathogen Stromatinia gladioli (synonym Sclerotinia gladioli). This soil-borne fungus primarily targets the corms and root systems, leading to necrosis and eventually the complete decay of the plant's underground organs.

While the disease is most destructive to gladiolus crops, it poses a significant threat to a wide range of bulbous iridaceous plants. The pathogen survives in the soil for several years through the formation of resistant structures called sclerotia, which are capable of remaining dormant until favorable conditions arise.

Infected plants exhibit yellowing and wilting of the foliage, often starting from the tips and progressing downwards. On the corms, the disease presents as small, sunken, reddish-brown to black lesions. Over time, these lesions expand, and the interior tissue of the corm may become hard, mummified, or entirely decomposed, often covered with tiny black sclerotia.

The development and spread of Stromatinia gladioli are significantly promoted by cool to moderate temperatures and high soil moisture levels. The fungus frequently enters the corms through natural openings or wounds sustained during harvesting, cleaning, or planting, spreading rapidly in storage if ventilation is inadequate.

Effective management requires a combination of strict sanitation, appropriate crop rotation, and chemical intervention. Growers should ensure that all planting material is inspected for signs of rot and treated with appropriate systemic fungicides. Avoiding acidic soils and improving drainage are critical cultural practices for reducing the risk of infestation.

• Rotate crops to prevent the buildup of soil-borne inoculum.
• Practice thorough drying and curing of corms after harvest.
• Remove and destroy all infected plant debris from the site.
• Use certified disease-free corms for new plantings.