Yes. You have powdery mildew. You need to take care of it because it will make your buds harmful to smoke. I had this problem with my White Widows in the late flowering stages, and I solved the problem pretty easily after I did a bunch of research because I didn't want to spray anything on my buds.
Try a mixture of 1 part skim milk and 9 parts water. Mist your plants with this for a few days, but make sure you have a dehumidifier going at all times. Powdery mildew is made up of spores that land on leaves and germinate under humid conditions over 50% and temps that are under 76. I was keeping my humidity in the 40s, but I ended up lowering it to the 30s because it was still spreading over my leaves. The problem has been resolved and my buds still smell and look great.
Hope this helps you out!