Powdery Mildew Remedies for Plants | Old Farmer's Almanac
There is no sign of it on other susceptible plants such as phlox. Causes of Powdery Mildew. This is probably due to the fact that it is not caused by just one fungus but by several different species that are attracted to different kinds of plants. The powdery mildew that you find on your squash is not the same as the mildew on your beans or roses.