How to Manage Pests

Pests in Gardens and Landscapes

Damping-off diseases—Pythium and Rhizoctonia spp.

Several soilborne fungi, including Rhizoctonia spp. and water molds such as Pythium, thrive under wet soil conditions. Infected roots become soft, mushy, darkened, and decayed. Water mold fungi also cause "damping-off," the death of seedlings that collapse at the soil line under damp conditions. More mature plants infected with Pythium grow slowly and may gradually decline, exhibit terminal dieback, and die.


Prevent damping-off diseases by preparing the site well before planting and providing appropriate cultural care, especially proper irrigation. Solarizing the soil before planting can reduce Pythium and Rhizoctonia fungi.

Browning and death of shoots
Browning and death of shoots caused by Pythium. This bare root rose developed damping off disease after cold storage and excessive moisture.

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2017 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   Contact webmaster.