Powdery Mildew
In our previous article, we took an extensive look at one of the most common molds: Powdery mildew. Yes, it’s so important that we dedicated an entire article to identifying, preventing & treating it. But while it is a common fungal pathogen, there are many others to look out for. As you all know, prevention is better than cure…
Botrytis (Bud Rot)
Botrytis, commonly known as “bud rot”, is another common fungal infection that occurs in environments with poor air circulation and high moisture. This is a very difficult mold to detect, initially. It makes itself apparent as the sugars in the leaves begin to discolour and start drying out. It usually occurs right at the base of the sugar leaves, where they meet the bud. If you leave this untreated, the bud rot will result in large dead spots on flowers and fluffy white growths.
To avoid this fungal infection, keep the humidity relatively under 50% and ensure you provide good airflow within and around the plant. If you do notice bud rot rearing its ugly head, it’s important to remove affected buds immediately to prevent them from spreading and contaminating the rest of your plants.
Fusarium
Fusarium is a soil-borne fungal disease. It is particularly hard to detect and get rid of. This pathogen causes your plant to suffer from wilting, stunted growth, root and stem rot, and reddening of the xylem.
Fusarium ultimately will obstruct the xylem (plant veins) and prevent any water from being delivered to the leaves and flowers above the blockage formed. This is what leads to the wilting and the eventual death of your plant. Fusarium is especially hard to get rid of. This fungus can lay dormant in your soil for very long periods of time, before emerging during hot weather conditions.
If you notice any of the above symptoms, you are more than likely dealing with this pathogen. This is a devastating disease to contract because the only way forward is by removing and destroying any affected plants - and doing so ASAP! It is advisable to avoid using this section of your garden again in future. Soil that has been infected by fusarium should be left dormant and be allowed to rest for at least 4–5 years before you are able to use it again. Alternatively, you can remove the contaminated soil and replace it with fresh soil.
Sooty Molds
Sooty mold is a type of fungus that can infect your cannabis plants after they have been attacked by a pest. These generally start to infest after an insect has bored into the marijuana plant's leaves and exposed the plant sap. This type of mold does not attack the plants directly, however, it can still be problematic. Excessive growth can block out light and prevent all-important photosynthesis.
Sooty mold gets its name from the dark black substance found in fireplaces, soot. This kind of fungus can appear dark brown too. In the early stages of growth, it will appear as a fine layer of powder. Then it will develop into a thick sheet if it hasn’t been monitored. This mold affects plants all year round and is particularly abundant during a pest infestation.
This pathogen can be treated without using chemicals. Wiping leaves or spraying them with lukewarm water is enough to get rid of the infection for a period of time. The fungus may return but water is enough to keep it at bay before harvesting.
Pythium (Root Rot)
Pythium is a type of fungi that includes over 150 species. Certain species are free-living in the soil and harmless to your cannabis plants. But certain species are pathogenic and can infect animals, plants, and fungi alike. Pythium fungi can cause especially substantial damage to plants in the seedling stage.
Commonly referred to as “root rot”, its natural habitat makes it hard to detect. Brown discoloration near the roots of the plant, a foul smell, and wilting and collapsing plants are the first signs.
Pythium thrives when overwatering has occurred. Giving your plants too much water creates the perfect environment for mold: excess moisture and lack of air in the soil. To prevent pythium from setting in, you should only water a cannabis plant when the top inch of soil is dry.
Growing cannabis has never been more rewarding than it is today. However, a lot can go wrong very quickly, if you are not on top of your plant’s environment. Yes, there are many aspects to constantly be checking, and things can change overnight. So, it’s best to be in the know and never get caught off guard.
We hope this article has helped you to identify and deal with the various molds and fungi that commonly attack weed plants. Autoflowering strains grow quickly and, hence, are naturally resistant to mold issues due to their speed. But with a little knowhow, you can keep fungi at bay when growing any of our world-class marijuana seeds.
