Ask-a-Dave's-Gardener: Problem with Stellar Pink Dogwood, 1 by Aken76

Aken76 wrote:
Hello,

About 6 weeks I had a Pink Stellar Dogwood planted in my front yard. I've recently been noticing the leaves aren't looking quite right. Some are turning brown at the tips and curling, not like just normal seasonal color change. I found something quite strange while looking closely at it this morning. These little white things on both the top and underside of a leaf. Please see images. Can anyone please help me identify it this is disease or insects. And how can I treat it?
Thank you in advance, greatly appreciate any info and advice!