White powdery mildew in late flower

I've had quite a bit of experience with WPM. Honestly unless its an outdoor plant, anything in store usually has sulphur which you dont want on your p)ants for smoking. (Outside rain can wash away) And anything natural, you can make at home. A tsp of baking soda per cup of water and just spray on leaves daily will PREVENT further growth by changing the surface pH on the leaves. Doesnt hurt, if the baking soda builds up, so just a water spray one day. Also do it when the lights just turn on so it will dry out. Any buds that have had their sugar leaves or deeper infected, i wouldnt reccommend smoking anymore. I use for edibles still though. If you have a bunch of WPM like that; I HIGHLY reccomend you use 1/4 cup milk and 3/4 cup water spray with the baking soda. Do this daily for a week. Milk is widely used by many gardeners as sunlight and fake sunlight will turn the milk proteins into a natural antiseptic and literally kills the WPM. Never noticed any change it taste or potency Your WPM probably started somewhere with less light and air flow. Once the WPM is under control, do what you can to fix this until the end of your grow to stop it from returning. Use LST to open that area up, or add a fan closer to there. Good luck!