Marijuana growers need to learn about the common diseases that attack and have the ability to destroy their harvest of the precious cannabis buds. The most serious of these problems are briefly described here.
The first problem is that of nutrient lockout or nute burn. This occurs when your cannabis plants are unable to use the nutrients that are available to them in the growing medium. This usually occurs when the concentration of salts has built up too much in the medium or the cannabis plants are suffering from toxicity.
Nutrient lockout or burn can be eliminated by leaching the growing medium. This is done by using fresh water (RO water) to clean the soil or other medium. The plant should then be left for a few days, until normal growth has resumed. New nutrients should only be added after the nutrient lockout condition is reversed.
This condition is usually noticed by observing yellow leaves that lose their turgidity. The pistils of the flowers may also turn to indicate nutrient lockout. The pH of the nutrient solution added to cannabis plants should also be observed to be within the optimum level.
Spider mites are a common pest for weed plants. They belong to the family of mites and spiders that all produce a silk web. They grow on the underside of the leaves. Spider mites thrive on dark and damp conditions. They become a serious problem for new growers, who do not leave ample room between the developing marijuana plants. They produce yellow spots.
Thrips are small insects that are also known to attack weed plants. They are fast creatures and are difficult to spot. They suck on the vital nutrients, and produce silver or bronze colored spots on the cannabis plants. Thrips usually start off as worms and develop into fully winged insects.
Spider mites and thrips should be defeated by using neem oil treatment. These pests are also reduced by providing ample light to the plants, and ensuring that damp conditions are avoided as much as possible.
Neem oil should be mixed with water and a wetting liquid should be added. This mixture should then be used to especially treat the underside of the affected leaves. This treatment should be given as early as possible, when the weed plant is in its growing stage. This treatment should be given when the grow lights are off.
Bud rot is another serious problem faced by the plants and occurs due to a fungus, named as Botrytis Cinerea. This fungus destroys cannabis buds from the inside by producing a brown sludge. This fungus usually requires damp conditions and stale air, and therefore can be eliminated by improving the conditions in your marijuana garden.
Powdery mildew (PM) is another fungal disease, which can attack the plants even in dry and warm conditions. PM can easily destroy a cannabis plant, if left untreated. It is identified as a white dust on the plant.
Sulfur burning can be used to treat PM during the vegetative stage. Organic sprays are also available to treat PM, once your marijuana plants have entered the flowering stage.