Iam using this dutch masters reverse at the moment. you spray the plants on the first week of flower then again on the 3rd week i am only on the 3rd week of flower at the moment so cant say if it has worked all i can say is that the guy at the hydro shop told me that the product isa cure as well as a preventive measure. also if you are going to get it buy a fair amount as it doesnt go that far.