Apple tree seedling

[sharon23]

Hi my son is growing an apple tree and was wanting to know if it was normal for the leaves to have a white powder on them the tree is indoors on my kitchen window.

[Chris]

That is a fungal infection, powdery mildew, it is somewhat common, you should put it outdoors in full sunlight, treat it with an anti-fungal spray of some sort, and hopefully it'll recover, but as a seedling it is very vulnerable at this point.