Hello Arnfinn - I like your aphids in white coats - they sound like tiny Medics. However, I am a little worried about the idea of sap sucking blithe trees. Even with a colon, it leaves a rather scary mental image. Might I make a tentative suggestion for your consideration?
White coated aphids
Sucking sap from blithe plum trees.
Hot breeze fans my face.
.Leo