How to Deal with White Powdery Mildew (WPM) on Cannabis Plants
WPM is a common fungal disease that affects a wide range of plants, including cannabis. It appears as a white, powdery coating on leaves and stems, and if left untreated, it can spread rapidly, compromising the health and yield of your cannabis plants. Let’s dive into the causes, dangers, prevention, and treatment of WPM on cannabis plants.
Understand that WPM is caused by various fungal species who thrive in warm, humid environments with poor air circulation. Cannabis plants are particularly susceptible to WPM during the flowering stage when humidity levels are higher and air circulation is reduced due to a denser growth structure. Beginners tend to mistake WPM for trichomes on the sugar leaves and often leave the problem untreated until it is too late.
The Dangers of WPM on Cannabis Plants
1. Reduced Yields:
WPM can significantly impact the growth and development of cannabis plants, leading to stunted growth, reduced photosynthesis, and ultimately, lower yields.
2. Compromised Plant Health:
As the fungus spreads, it weakens the plant’s natural defenses, making it more susceptible to other diseases and pests too.
3. Unsafe for Consumption:
Smoking cannabis with WPM can be extremely harmful to your health. The fungus and its spores can cause respiratory issues and allergic reactions, especially in individuals with compromised immune systems.
4. Contamination of Other Plants:
WPM can easily spread from one plant to another, potentially affecting your entire crop if left unchecked.
Preventing White Powdery Mildew
1. Lower Humidity Levels:
WPM thrives in high humidity environments, typically above 60% relative humidity (RH). To prevent its growth or slow it down, maintain RH levels between 40-50% or lower during the flowering stage.
2. Adequate Air Circulation:
Provide ample air circulation around your cannabis plants by using fans, pruning dead leaves or dense foliage, and maintaining proper spacing between plants at all times. Leaf on leaf contact creates moisture pockets where spores can grow and spread.
3. Keep Your Grow Space Clean:
if you’re growing indoors, regularly clean and sanitize your grow space walls, tools, and equipment to prevent the spread of WPM spores. Do not keep dead leaves or old moist soil nearby or in the same room.
4. Inspect Plants Regularly And Act Early:
Regularly inspect your cannabis plants for any signs of WPM, particularly in dense foliage areas. Catching the disease early can make treatment far more effective.
5. Choose Resistant Strains:
Some cannabis strains are more resistant to WPM than others. Autoflowers in general are less susceptible to WPM and other diseases. When selecting strains, consider researching their disease resistance properties too.
Treating White Powdery Mildew
1. Remove Infected Parts:
If you catch WPM early, remove the affected leaves and stems immediately to prevent the fungus from spreading. Dispose of the infected plant material safely, away from your grow space.
2. Homemade Remedies:
Several homemade remedies can help treat WPM, including:
- Milk Spray: Mix 1 cup of milk with 2 liters of water and spray on all affected areas. The proteins in milk help combat the fungus. Repeat every 2 – 3 days for 2 weeks.
- Baking Soda Solution: Mix 2 teaspoons of baking soda, a couple of drops of sunlight liquid soap, and 2 liters of water. Spray on affected areas every 2 – 3 days for 2 weeks.
3. Neem Oil:
Read the instructions on the purchased bottle otherwise mix 2 teaspoons of neem oil, 1 teaspoon of liquid soap, and 1 liter of water. Spray on affected areas once per week.
4. Ludwig’s insect spray:
Ludwig’s Insect Spray is a great all natural remedy mostly made up of garlic extract and other essential oils. It is not harmful to your plants or to humans and can be sprayed on your plants right throughout its life cycle. A strong smell of garlic may be present when you have treated you plants and when used very late into flower it can also affect the taste of your buds, but won’t harm you
5. Rose Care:
Rose is great for the vegetative state but only really suited for extreme infestations. This is one of the best pesticides for cannabis if applied carefully, but it comes with a nasty warning label so use at your own risk. There are various commercial products available that can effectively treat WPM. However, it’s crucial to choose products that are safe for use on cannabis and to follow the manufacturer’s instructions carefully.
6. Copper Soaps:
Copper soaps are an effective fungicide for treating WPM on cannabis plants. They work by disrupting the cellular processes of the fungus, ultimately killing it. Mix according to the manufacturer’s instructions and apply to affected areas. It’s important to note that while copper soaps are generally safe for plants, overuse can lead to copper accumulation in the soil, which can be harmful in high concentrations. Use as directed and monitor your plants for any signs of stress.
Note: Avoid Fungicides or Pesticides During Flowering: Applying these during the flowering stage can be dangerous, as the chemicals may end up in the final product, making it unsafe for consumption. If you must use pesticides during flowering, make sure they are specifically labeled as safe for use on consumable crops and cease application at least 2-3 weeks before harvest.
Conclusion:
The importance of an early preventative treatment before WPM is even visible cannot be overstated! Prevention is always the best approach. Treat your plants with some of the above treatments before entering the flowering stage even if no WPM is present.
At Seed and Soil, we understand the importance of proactive plant care and disease prevention. Our team of experts is dedicated to providing you with the knowledge, resources, and products you need to keep your cannabis plants healthy and thriving.
From high-quality seeds to organic pest and disease control solutions, we have everything you need to successfully navigate the challenges of growing cannabis. Visit our website to explore our range of products and educational resources, and join our community of passionate cannabis cultivators today.
Sub Topics
Featured Products
Featured Guides
Sign up to our Promotion List
