Gladiolus Dry Rot
Gladiolus foilage yellow and dying? Peppered with black spots? Could be dry rot. Find out more about this fungal disease and what to do.
What is it?
A plant disease caused by the fungus stromatinia gladioli, which attacks corms in storage and the soil.
What does it look like?
Foilage turns yellow and dies. Leaf bases are rotted or shredded. Black spots of the fungus, which look like pepper, cover the leaf bases and corms. Corms have dark brown to black lesions, which sink inward. The lesions are dry, corky and may join together to destroy the entire corm.
How does it manifest?
Fungi of this species penetrate root corms while in the ground or storage. Decay quickly spreads up into the leaf cases. Dry rot is most likely in corms that have been stored in moist conditions, or planted in wet, cold soil. The infection spreads through contaminated soil and corms. The black pellet-like spots that form on the corms can survive for up to 10 or more years in the soil.
What can you do about it?
Any plants which show signs of infection must be discarded. Dig corms up before the onset of cold, wet weather and always store them in a dry place. If you need to replant in an area which held previously infected corms, first treat the area by fumigating the soil with metam-sodium. Plant in well-drained soil only.