Diseases to Cannabis
One of the worst things imaginable to any grower is having a once-healthy vegetating or flowering marijuana plant fall victim to a preventable disease such as gray mold, deprivation illness or some other potentially fatal disease. However, there are several steps that can be taken to prevent these illnesses from occurring in the first place, as well as measures to bring disease-ridden plants back to health. There are literally hundreds of diseases, bacteria, viruses, molds, etc. known to cause harm to Cannabis. The following list, however, are the most common ones experienced by most North American growers.
Gray mold is a disease that, if left untreated or unnoticed, can kill an entire plant or even garden. It is most commonly seen during maturity in the flowering stage of the female Cannabis plant. Medical marijuana growers whose plants experience gray mold will first notice the tips of the leaves begin to turn a yellow-brown color, eventually wilting completely. This is followed by the pistils on the buds turning an unhealthy brown. This then advances to the tops of the nugs, where a fuzzy, gray mold begins to develop, reminiscent of strawberries that have been left out for a few days. If left untreated, this mold then spreads to become a grey-brown fuzzy slime that will then kill the entire crop.
To help prevent gray mold from occurring in the first place, make sure that your garden has humidity levels below 50% with plentiful ventilation. Like most other molds, this disease thrives in warm, moist climates with stagnant air. However, sometimes no matter how many precautions are taken, diseases still plague Cannabis plants. If you notice the beginning stages of gray mold occurring (yellowing of the tips of the leaves and even wilting), immediately remove the affected area by cutting off the discolored part of the leaf and add more ventilation, ensuring the humidity in the area is even lower. Unfortunately, once the buds are affected, your plant likely has little chance, but you can still remove the infested cola.
Deprivation illness is an easily preventable disease to marijuana that is caused simply by a lack of some necessary food or other nutrient. Needless to say, one way to ensure your hard-earned garden remains healthy is to continue providing it the necessary nutrients is requires, namely NPK (nitrogen, phosphate and potassium). If a plant is not receiving enough nitrogen, the lowest leaves will turn yellow, and if left untreated, fall off. If there is a shortage of phosphate, the leaves of the plant will turn a deep green, while not growing any larger in size and the lower leaves may yellow and wilt. The pH value is key to a plants health, especially in the case of potassium. If the soil is too acidic, the plant will not be able to receive enough calcium or potassium. In the case of a lack of potassium, the tips of the leaves will start to turn yellow, eventually spreading to the entire leaf, turning it a brown-yellow color. Shortages of iron, while rarely seen, cause the leaves to yellow and droop.
Mildew can mainly be prevented by controlling the growing environment of your garden. Different from most other moulds, mildew thrives in an environment with low humidity. While it is rarely seen in marijuana plants, it can cause the top of the plant to rot. The first sign of a mildew infestation is the leaves at the canopy yellowing and becoming weak. One of the most frustrating things about mildew is that it doesn’t usually rear its ugly head until the last week or two of the flowering period. Much to the utter dismay of growers who experience mildew, the entire top of the plant must be removed in order to ensure the entire plant does not become infected.
On the reverse end of the spectrum, pythium is a disease that affects the root system of marijuana plants. One of the most drastic outcomes of a pythium-infected plant is it falling over completely due to a lack of support at the base of the stem, where it has turned brown. Pythium causes the lowest part of the stem to rot, as well as the roots. This mould thrives in a moist, humid environment and can only be spread directly through water.
To prevent a pythium infestation, keep your soil or rockwool at a consistent temperature. When there is a large variation in the temperature of these, it creates a “window” for the pythium spores to manifest themselves on your plant. If your garden or plant has is showing signs of a pythium attack, chemicals may be used, but only in frugal amounts.