Powdery Mildew is a fungal disease that can affect almost any plant. It can first show up appearing like fluffy white cotton on the leaves of your plants. Fungal spores are always present in the environment and float through the air until they can find a suitable place to grow. If they find their way into your garden they can cause massive damage if it goes uncontrolled. Because powdery mildew is everywhere already, the best way to control it is through prevention. When planning a new garden or growing space always think about questions like what will happen to the room if it gets cold? Will there be condensation in the area that causes standing water? Is the humidity so high that the fungus has the opportunity to grow?
Powdery mildew exists as a filamentous fungus that grows into the plant tissue and will continue to survive in the plant tissue even if you try to wipe it off. If you clone this plant or take it somewhere else, there is a chance you could spread the infection The plant will always have that infection unless you take serious steps to grow the plant without the fungus. If you have a valuable variety that is infected it can be really hard to maintain a healthy plant. This can involve costly tissue culturing and washing of the plant tissue. After spending all of that time and money on a precious variety there is no guarantee that the fungus won't re infect the plant. This is why powdery mildew is best controlled through environmental conditions rather than relying on treatment after infection.
The first step to beating powdery mildew starts before you even have plants. A grow room should be designed to have adequate airflow around all of the plants, as well as prevent dead spots where the air does not circulate. Try to avoid packing plants too tightly and maintain proper humidity helps to keep standing water off of your plants. Some growers incorporate silica products into their nutrient feedings to help strengthen the cell walls of the plant, allowing it to resist the fungal invasion. Some new methods of control are being developed and implemented, but they do not work well in every case. Newly identified hyperparasites are fungi that attack the powdery mildew just like the mildew attacks the plants. Currently they are not as effective at treatment for every situation as prevention is, but once you have a problem it can help slow the spread and prevent some damage.
Powdery mildew affects the strength of a plant and can make it susceptible to other diseases. This means sometimes it is just better to get rid of an affected plant rather than trying to rid the plants of the infection.