How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Seed piece decay

Seed piece decay is usually caused by the combined action of the Fusarium fungi that cause dry rot in potatoes and the Erwinia bacteria that cause blackleg, although decay can sometimes be caused by Fusarium alone. Fusarium spores are present virtually everywhere in the soil. They germinate and infect the freshly cut surfaces of seed pieces, causing lesions that later may be invaded by Erwinia. When seed pieces are infected by both Erwinia and Fusarium, losses from seed piece decay are much greater than when Fusarium is present by itself. Cool soil that is too wet or too dry favors the development of seed piece decay.

Dry rot in potatoes caused by Fusarium  spp.
Dry rot in potatoes caused by Fusarium spp.

Erwinia  in potato tuber causing blacklegErwinia in potato tuber causing blackleg


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/GARDEN/VEGES/DISEASES/LIFECYCLE/lcseedpiecdec.html revised: April 25, 2014. Contact webmaster.