looks like crystal formation to me! You get THC on the fan leaves near the buds first, its more some thing to be excitred about!View attachment 2450893here is another picture
That is called Powdery Mildew, or PM. It is systemic, meaning it is IN the plant not ON the plant. There are multiple means of treatment, but no cure. I suggest Green Cure or Serenade. Both are OMRI certified and can be used up to harvest. These are ultimately sprays that will help keep the mildew from growing. You may need to use it weekly. You can use it up to harvest, follow instructions on the label. You do NOT want to smoke mildew! It is harmful to your lungs!View attachment 2450893here is another picture