not that I've had a lot of trouble with these sorts of things, but for basically anything organic, I spray with a dilute solution of H2O2, hydrogen peroxide.

I began with solutions in the 3.5% range and reduced to .75% solution. it doesn't seem to impact the plant in either veg or flower but works. but best not to get too much on the soil as it kills all the good microbes working down there.
Farang Reviewed by Farang on . Powdery Mildew, Spider Mites and Thrips. AAAAH Hello, So two/three weeks ago i noticed some white dandruff like powder on my plant leaves. They started on the lower leaves and worked their way up. I thought it was powdery mildew until today when I noticed stuff on the underside of the leaves. I had sprayed them three times with milk and baking soda and a little bit of dish washing liquid soap. I bought cannacure (CannaCure Spray 750ml Spidermite Pest | eBay) yesterday and sprayed them, but they look worse today than they were Rating: 5