I first raised the alarm on boxwood leafminers (Monarthropalpus flavus) in a BYGL Alert posted in late March (see "Blistered Boxwoods and Hissing Hedges", March 30, 2017). That report focused on alerting landscape managers that high localized populations were producing heavy leafmining symptoms that could be mistaken for winter injury.
I began receiving reports this past weekend that boxwood leafminer midge fly adults were emerging en masse in parts of Greater Cincinnati. Indeed, I visited heavily infested boxwoods in a local park yesterday and was treated to clouds of the tiny flies billowing around the foliage. Some leaves still contained pupae while others had pupal skins hanging from lower leaf surfaces signaling that flies had left the building.