mark under leaves of apple tree

Question

I have pink/white marks under the leaves of my apple tree. Please help me understand what this is on my apple tree. It has what I think is rust but also this pink/white almost fluffy marks underneath. Are they eggs or disease? I’ve looked in books but to no avail.

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Answer 1

That looks like powdery mildew to me. For more information on powdery mildew and other apple tree diseases, please visit the following link:
https://www.gardeningknowhow.com/edible/fruits/apples/apple-tree-diseases.htm