I live in Middleburg, Fl. In one section of my yard, I have two sago palms. One started getting white spots that looked similar to a mold. I sprayed it with Immunoz, but it continued to spread and got on the one next to it. The prongs of both plants did touch each other as they are only four feet apart. Anyway, it spread to the other one as well. I read your how to prune sago column, unfortunately, after I had already pruned them. The worst infected one has no prongs left and they all had the spots; the other has four prongs left. Help !!!
Sick Sago Palm
Certified GKH Gardening Expert
It is probably powdery mildew. This article will help:
You can treat it with either a chemical fungicide or neem oil. Both should be available at any store that sells gardening supplies.