The big three cannabis diseases

Added on 25 August 2023

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How to prevent and manage the top diseases affecting cannabis plants. Several factors can affect the production of a healthy cannabis crop — diseases being among the most common and difficult to control once established. GPN recently caught up with Tami Van Gaal and Erica Hernandez, division leader and technical specialist, respectively, at Griffin Greenhouse Supplies, to learn how growers can identify, control and prevent the three most important diseases found in indoor cannabis production: powdery mildew, Botrytis and hops latent viroid.

Powdery mildew and Botrytis are two foliar diseases capable of decimating a crop if left unchecked. Both of these spores are fairly ubiquitous in the environment, making it hard to completely eliminate exposure. Of the two, powdery mildew tends to be harder for growers to control and the biggest reason for that is the disease organism gets into the interior of the leaf.

The signs that we see — the white powdery growth on the exterior of the leaf — is sporulation. By the time that happens, the mycelium are all over the place inside the leaf. Where Botrytis, on the other hand, is penetrating the leaf surface but doesn’t hide within the cells within the leaf. It’s generally penetrating from the outside in.

Botrytis

When it comes to preventing Botrytis, get all of the debris out of the greenhouse and, remove any foliage that isn’t healthy or isn’t going to recover for any reason at all. It could be as simple as everybody brushes up against one side of the bench and those leaves or branches start to get bruised — get them out of there.

Photo caption: A botrytis infection, or bud rot, causes buds to turn brown and die. Leaf and flower material is killed when a botrytis infection turns into necrosis. Photo: Griffin.

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