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White powdery Mildew
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White Powdery Mildew, also known as White Powdery Mold or WPM, is a fungus that can infest cannabis plants. It appears as white patches of powdery growth on the leaves and stems, resembling flour. If left untreated, it can spread rapidly and cause damage to the plant, rendering the affected buds unusable.
Cause of Issue
◉ High Humidity: WPM thrives in environments with high humidity. This can be problematic for cannabis growers, especially during the flowering phase when humidity needs to be lower to prevent the growth of WPM and bud mold.
◉ Low/No Airflow: Poor air circulation allows WPM to settle on the plant. Having proper airflow in the grow room, achieved through fans, can help prevent the growth of WPM.
◉ Poor Ventilation: Lack of fresh air exchange in a closed grow area provides multiple opportunities for WPM spores to land on plants and reproduce. Proper ventilation is essential to reduce the risk of WPM infestation.
◉ Leaf-on-Leaf Contact: Leaves that touch each other can create a moist environment, making them more susceptible to WPM. Pruning excessive foliage and ensuring leaves have enough space can help prevent leaf-on-leaf contact and minimize the risk of WPM.
Symptoms
◉ Presence of white, powdery patches on the leaves and stems of cannabis plants.
◉ The patches may resemble flour or powder and can easily be wiped off.
◉ If left untreated, the patches can spread and cover larger areas of the plant.
◉ Infected leaves may show stunted growth or yellowing.
◉ In severe cases, the affected leaves may wilt or die.
◉ Buds contaminated with White Powdery Mildew should be discarded, as they likely contain a high number of spores.
Corrective Actions
◉ Milk: Mix one part milk with three parts water and spray it on the affected plants. Ensure both sides of the leaves are thoroughly wetted. This treatment can be applied while the grow lights are on.
◉ Potassium Bicarbonate: Dissolve one tablespoon of potassium bicarbonate in one gallon of water. Optionally, add one tablespoon of vegetable oil and three drops of liquid dish soap. Spray the plants lightly but evenly.
◉ Baking Soda: Mix one tablespoon of baking soda, one teaspoon of liquid dish soap, and one gallon of water. Spray the solution on all leaves, covering both the top and bottom surfaces.
◉ It is important to remove White Powdery Mildew from the affected leaves by gently wiping them with wet paper towels or a cloth. Proper airflow and ventilation should be maintained in the grow room, and fans can be used to circulate the air and prevent WPM from settling.
◉ Remember, early detection and treatment are key to effectively combatting White Powdery Mildew and protecting your cannabis plants.
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