I have both impatien walleriana and New Guineas on my windowsill (facing west). Recently, I noticed the new leaves are growing out disfigured. The leaf shape is fine, but on the leaf surface, there numerous small, round "dents" or "pits". Both types of impatiens have gotten these weird leaves. The older leaves are fine. What is this? Is this anything to worry about?

There are no sign of bugs, mold,etc. I water them when dry, and fertilize weekly. I hope it's not a bad disease.

Thanks for any help!

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~Lily