I will address this to Janet & Steven, although I more than welcome anyone's expertise. I first noticed this prevalent tiny white scale two years ago on the Bradford pear street trees in front of our house. (Hey, I didn't buy them! Glad Ohio finally added problematic ornamental pears to the "Invasive Plants Banned in Ohio" list). We live in the Greater Toledo area (Waterville) 15 miles from the Michigan border.
Upon closer examination, the same scale was in our front and back yard on a 6 year-old Corylus americana filbert bush and sweet bay magnolia and an existing lilac. Although I am not a fan of any commercial chemicals, I had an arborist treat them (July 2018 with Transtect/dinotefuran bark spray; a drench with the 30' pears because of height) on the advice of a landscaper who stated scale had taken over many of her yard's woody plants when she didn't treat.
This year's scale tally appears to be: gone on the pears and sweet bay magnolia, but prevalent on the filbert and lilac... with the addition of our serviceberry! The filbert and lilac both have curled leaves and the serviceberry has always struggled.
I understand scale can be treated with dormant oil when the pest is in the crawler phase. i mailed a sample to Ohio State University's Plant & Pest Diagnostic Clinic yesterday for ID and subsequent pinpointing of when the crawler phase occurs. Based on a photo last year, Dave Shetlar, OSU's beloved retired "BugDoc", offered the possibility of Scurfy scale.
Anyone know this scale? The plants are too large to lightly "scour" them off with abrasive pad. We are growing the filbert to harvest nuts for our table. Likewise with the serviceberry, although the berries have been too scanty so far (likely cause the ever present-day stem-girdling-root problem). If we don't treat the scale again, what are the likely/possible consequences?
Waterville (Toledo) OH