Fusarium Bulb Rot

Fusarium oxysporum sp. cepae

Also known as Fusarium Basal Rot, this is a variety of Fusarium that specifically attacks members of the Allium family (onion, garlic, shallot and chive). The fungus gets into the bulb through small wounds (these may be caused by tools, insects or onion maggots) and enters the leaves, causing them to turn yellow, wilt and die back at the tips. It then moves down into the neck and bulb, making them soft and squishy (a white fungus may be visible at this point). Often the bulb doesn’t show any symptoms until after harvest.

Remove and destroy infected plants. Keep onion maggots under control as their damage often allows the fungus to enter the bulb. Some varieties are resistant. Store the bulbs in a cool, dry place after harvest.

Image: Howard F. Schwartz, Colorado State University, Bugwood.org