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