Our grow is susceptible to fall victim of this systemic mold infection. However hard-to-beat it may seem, there are some techniques that could effectively prevent or destroy it. This fungus loves warm and damp environments and uses other animals, such as caterpillars, to move around and reach cannabis plants. Besides, it’s extremely contagious. Separate any infected plants from the rest as soon as possible to avoid further damage.
Also known as gray mold, botrytis is a parasitic fungus that can attack our cannabis plants at any time. It's important to know that there are some conditions that favor its proliferation: high humidity levels, sudden changes in temperature or heavy rainfalls. But that's not all. Apart from the weather conditions, there are other elements that could dramatically raise the likelihood of our plants being affected by botrytis mold as is the case of the caterpillars living on or close to our plants. Their droppings can be a possible source of infection.
Everybody knows that the flowering stage is a delicate moment for irreparable damage can easily be caused and this fungus is particularly difficult to fight. However, knowing how to take preventive action or how to react when it's already settled could help you kill it for good.
1-Know your enemy: its life-cycle
In order to know what you're dealing with, you first have to learn how it is born and how it spreads.
Gray mold is commonly found on dead plant matter, where the disease can overwinter as mycelium. At this point, if temperatures go up, they'll start to spread like wildfire, which explains why it is in spring and in autumn (increased rainfall and moisture) that they're more likely to appear.
In broad daylight, vegetative mycelia start to produce conidiophores with clusters of conidia that are later released and carried by air currents until they reach stems and leaves. Botrytis cinerea conidia are asexually produced spores that can remain alive for years until the conditions are favorable enough.
2- Remain vigilant
A major problem for cannabis growers is that identifying an infection at an early stage is not easy for buds don't seem to be affected. One of the most evident indicators is the stems', leaves', and branches' necrosis, a moment in which some parts turn brown and kind of damp. Another symptom indicating the presence of botrytis is the appearance of brown circles on the buds, giving them a dead look.
3- Prevention is always better than cure
The best way to prevent this infection from spreading all over your grow is by making sure none of your plants is in contact with any parts you believe might be infected. Their being too close will facilitate airborne infection. If a spore sets on your plants, they're very likely to end up infected. So, upon the slightest suspicion, remove and burn those parts that may be infected and keep the plant away from the rest.
4- Keys to fighting botrytis indoors…
If you're growing indoors, ensure proper air circulation and keep a close eye on the irrigation schedule. This way you'll make sure humidity levels remain low, which is essential to the well-being of the leaves and flowers. Never let moisture content exceed 50%.
Don't think dangers will be over after the harvest for your flowers will still be at risk long after it. During the drying stage, it's very important to maintain the maximum absolute level of humidity lower than 60%, with proper ventilation too. The best way to do it is by installing a small extractor equipped with a carbon filter that keeps the air moving and makes moisture levels go down.
There are two elements that make open-air grows more susceptible to the attack of botrytis: rainfalls and the dense canopy of cannabis plants. During summer, when plants are still growing and flowers haven't reached maturity, they're quite unlikely to be attacked by this fungus because it's during blooming, by early October more or less, that the weather starts to change and rainfalls become more common, resulting in poor circulation and excessively high moisture levels.
In any case, pruning is highly recommended for botrytis mold loves dense and bushy plants. Similarly, we can look for a growing method that allows for larger spaces between plants and teaches them to grow in such a way that they don't become too thick.
6- Keep caterpillars at bay
Warding off plagues, especially if they are caterpillars, is very important because plant cuticles can get damaged and make it easier for the fungus to get inside. Take preventive action during summertime to prevent this from happening. This way, you'll restrict their presence during flowering. And remember: for preventive treatments to be effective, make sure you put all your heart into them.
7- If all else fails…
If preventive action doesn't lead to the desired results, you can always use Neem oil, a very useful antifungal solution to fight infections caused by mildew, powdery mildew or botrytis, among others. Plant protection products shall work equally well. The market is full of options. All you have to do is pick the one that best suits your situation. For doing so, you have to be fully aware of the risks posed by this infectious fungus and decide on the products and the intensity of the treatment accordingly.
Otherwise, the results could be rather disappointing and, instead of killing them, they'll become stronger than before if you fail to use different products. Should the problem persist, try repeating the treatment every week gradually increasing the frequency if you feel it's not enough.
8- And remember: cleanliness is absolutely essential
Lastly, making sure the area we're growing our plants in is 100% clean is the best way to prevent the attack of the so-dreaded gray mold. Do not forget to remove any infected parts of the plants either. If you decide to cut a flower, make the cut at least 3 cm below it, after which it should be burnt so it doesn't infect other plants. The tools you use while doing so must be properly sterilized and you should avoid touching the bud because the fungus can be transported through the air and with the help of our hands.
Under no circumstances should infected buds be consumed because they could cause lung issues. Besides, the taste of moldy weed is rather nasty.