what color should a raspberry primocane be? Ours start out being green, but soon get a whiteish color to them which can be rubbed
off back to the green. Is that powdery mildew? Patch gets lots of sun, has good drainage, but is in a "wild area" and there isn't good ventilation.
This does describe powdery mildew! Luckily this can be treated, and doesn't really pose much of a risk to the health of the plant. This article will help: https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm