What is Botrytis or Gray Mold?

Written by on 19 July, 2020

As a grower it is very important that you know what Botrytis (Botrytis Cinerea) or Grey Mold. Well, this is a parasitic fungus that affects many plants, (including marijuana), which also has different forms of it, such as Botryotinia fuckeliana, Haplaria Grisea and Botrytis Vulgaris.

Botrytis manifests itself in cannabis as a grey mold and is considered a necrotrophic and saprophytic fungus; it also spreads rapidly and can damage your growing in a short time.

At what stage of the plant can it appear?

Grey Mold can be present mostly at the end of the flowering stage or during the drying of the cannabis; however, you need to understand that it can also be present during the entire life cycle of the marijuana, even at harvest, so you need to be very careful.

Botrytis reproduces by spores that move through the air and are very resistant. In fact, they can remain dormant below 0 degrees or at extreme temperatures, and when given certain favourable conditions (such as humidity and ideal temperature), they can become active and affect cannabis plants completely.

In addition, if we add to these aspects the lack of ventilation of the growing place, we would be creating a perfect environment for the fungus.

Signs of infection

It is a bit complicated to detect a Botrytis infection early, because the signs that indicate such infection are usually visualized after about two or three weeks since the invasion of the plant began. When you notice it with the naked eye, it is probably very advanced.

Some of the most common symptoms that indicate that the plant is infected with grey mold are:

– Brown or gray parts of the plant that look dry.

– Leaves where necrosis is observed, and the affected area crumbles easily.

– Pale, greyish, and sometimes blue-green coloured buds. Also, buds with dry texture. In advanced stages of the infection, a kind of cottony layer can be seen.


Constantly check your growing (almost daily), and try to avoid the conditions for the appearance of this fungus, by maintaining factors such as lighting, temperature, humidity, ventilation, hygiene and the density of your growing, among others, at its appropriate point.

If you do not harvest in a hygienic way, the plant will probably be infected. Dried and stored buds can decompose and the fungus can be transmitted through the seeds.

It is also important to ensure that no insects (such as caterpillars) are present in your growing area, as they can transmit this fungus.

Take the necessary precautions not to spread the infection throughout the growing area, and above all do not use marijuana with Botrytis, as it could be harmful.





Current track