What are the white spots on my rosemary plant?
White Spots on Rosemary
Certified GKH Gardening Expert
It could be powdery mildew or a pest. This article will help you with powdery mildew: https://www.gardeningknowhow.com/edible/herbs/rosemary/white-powder-on-rosemary.htm
It may also be pests, possibly mealybugs. This article will help with them: