What are some of the best ways to fight or prevent powdery mildew (PM)?

Prevention is key with powdery mildew and keeping temperatures at all times above 70 are one of the best ways to do so as it thrives in temps below 70. Avoid large swings in temperature to avoid condensation build up on leaves. Defoliation or deleafing so that leaves are not sitting on top of each other which creates a safe haven for the mildew to grow. Airflow is also key to prevention. And lastly there are sprays that make claims to prevent PM, but we believe if you can do all of the above you will likely not have this issue unless someone brings it into your grow room.