Powdery mildew

Powdery mildew is a disease that affects the aerial parts of cannabis plants, especially in temperate and subtropical regions. It is relatively easy to detect by its symptoms. It is generally characterized by the formation of pustules or spots made up of powdery hyphal masses and fruiting bodies on the upper surface of the leaves. The color of the spots varies from white to grayish. The fungus can also affect other parts of the plant when the infection is severe and climatic conditions are favorable.

Powdery mildew feeds on its living host, sending haustoria into epidermal cells to absorb the necessary nutrients. This form of absorption irreversibly alters the metabolism of infected cells, such as respiration and transpiration.

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The affected organs eventually become necrotic and fall to the ground.

Control method

Applying preventative sulfur treatments will significantly slow the development of these pathogens. As always, removing accumulated plant debris from fields and cultivation facilities will reduce the density of the infectious inoculum.

To prevent this fungus, we should maintain a relative humidity in our grow room that does not exceed 65% nor fall below 40%.