Pythium Fruit Rot

HOSTS

• Cucurbits
• Solanaceae

DESCRIPTION

Pythium fruit rot can be caused by multiple Pythium species. In Utah, both Pythium aphanidermatum and Pythium ultimum have been observed.  

BIOLOGY

Pythium spp. survive in the soil without hosts. When moisture becomes available, Pythium will produce spores, some of which are capable of independent movement. The spores can invade hosts through pre-existing wounds or through direct penetration. 

SYMPTOMS

• Stunted growth 
• Discolored and wilted foliage and stems. 
• Fruit with water-soaked brown spots where the fruit touches the ground.  
• White mycelium growth on fruit lesions. 
• Rotted fruit, with collapsed walls. 

GENERAL MANAGEMENT

• Use certified disease-free seeds and transplants. 
• Minimize moisture by utilizing drip irrigation ensuring soils are well-draining.  
• Avoid overwatering, as wet soils increase the spread of disease. 
• Use plastic mulch and staking to keep fruit from being in contact with the soil. 

FUNGICIDES

Mefenoxam products used in soil drenches can reduce root rot. These are ineffective