How To Identify and Control Pythium (Crown Rot) on Cannabis Plants

Professor DeBacco


Pythium (Crown Rot) Identification
Several different pathogenetic species that can cause disease in a wide host range
Pythium is a water mold, so it can travel to new host plants via water
Root rot and lower stem decay cause aboveground symptoms such as marginal leaf scorch, stunting, poor vigor, and/or inconsistent stands. 
Can produce oospores that overwinter
Most notably causes root rot that can be field identified by pulling out roots and trying to strip the outer layer.
Above ground seedlings will damp off (common in propagation areas) and larger plants will express chlorosis of leaves
*Once Pythium infects hemp plants, there is no cure. 

Pythium (Crown Rot) Life Cycle



Common Methods of Spread
Soil/Substrate Transfer: Tools, containers, shoes
Contaminated water: Contaminated irrigation water, runoff
Infected plants: Should be isolated and removed (Tag and bag)
Winterover: inoculum present from previously infected plants, also poor sanitation protocols



Pythium (Crown Rot) Management
Manage soil moisture in root zone
Inspect any new plant material entering the growing area
Ensure proper aeration of substrate
Keep nitrogen at optimum and not excessive levels
Avoid salt accumulation in substrate

Have sanitation protocols in place even if this is not identified






Link to Lecture Slides: https://drive.google.com/file/d/1IBMV...

*Due to the description character limit the full work cited for "How To Identify and Control Pythium Crown Rot on Cannabis Plants" can be viewed at... https://drive.google.com/file/d/1jze4...