Powdery Mildew on Seedling Apple


5 year old buck +
I have one apple tree started from seed that's 10" tall and it has developed what looks to be powdery mildew. I looked it up on the web and there are numerous remedies and preventatives, some store-bought and some home-made. Does anyone have experience with a remedy that WORKS? I don't want to guess from so many choices given in internet articles. Thanks in advance.
Prevention and treatment of these kinds of diseases is part of a regular IPM spray program. If you have access to Rally (DMI fungicide), it's pretty potent on PM. But balanced, regular, spray program that includes insecticide, protectant fungicide (like Captan, or others), and a systemic fungicide (like Rally, and others), is really the key.