Onion Disorders: Botrytis Leaf Blight, Leaf Fleck, and Neck Rot

SKU A3803

Author(s) Karen Delahaut, Walt Stevenson.

Three types of botrytis diseases affect onion crops. Botrytis leaf blight is a destructive disease caused by Botrytis squamosa. This disease kills foliage and spreads so rapidly that growers nicknamed it blast. Botrytis leaf fleck, caused by Botrytis cinerea, is rarely an economically important disease and may occur at the same time as botrytis leaf blight. Botrytis neck rot, caused by Botrytis allii, is a destructive post-harvest disease.

Plants infected with any of these fungi are more susceptible to blast by other diseases, insect damage, mechanical injury, and air pollution damage. Find out how to identify, prevent, and control these damaging onion diseases in your home garden (2 pages; 2004).