Ask Ed: Questions and Answers – Root Rot and Stem Diseases

Question: Dear Ed,
I saw a package that said “trichoderma harzianum” as the active ingredient, what is that?

– Kevin

Ed’s Rosenthal: Dear Kevin,

Tricoderma harzianum is a fungus that protects roots from attacks by pathogenic fungi including the agents causing different root rots and stem diseases such as Pythium, Fusarium and Rhizoctionia, which all affect cannabis. The Trichoderma fungus sends hyphae out that pierce through the pathogenic organisms and suck their vital juices for food.

Tricoderma harzianum is harmless to humans, pets, fish and other organisms. Usually it is used as a soil drench to protect roots, but it is also used as a foliar application to protect leaves from fungal attacks.There are a number of products that use this organism as a fungicide. They include Plant Shield, Root Shield, Promot® MXM and MycoMaximum

Send your grow questions to Ed Rosenthal at [email protected].