Q.What Is That White Mold On My Plumeria And Other Plants And What Can I Do About It?
I have been squirting a 5% neem and water solution on it. It comes back. I use the flat sprayer on the hose and really turn on the pressure to clean it off and it comes back. I dont want to lose any leaves. The soil her is very sandy, poor but good drainage. Plants get lots of sun. Only one plumeria out of 4 gets and t hey are quite separated. Now a plant whose name I forget get it. I’ll look that one up. Very common n FL also used as a flowering hedge. Comes in dwarf also and red, orange, yellow, or coral flower clusters. This one is also far from the others. Could I be overwatering?
Certified GKH Gardening Expert
It sounds like powdery mildew, but make sure it isn't mealybugs which leave white cottony growth at leaf and stem joints. (info below). Powdery mildew can be treated with a fungicide suggested in the article below, however prevention is more effective than trying to remedy a fungal infection.
Most plants are not permanently harmed by powdery mildew except for fruit plants and if the mildew continues year after year.
Overwatering probably isn't causing the mildew as much as humidity. Make sure you don't wet the leaves when you water, always water from below.