Boxwood Leafminer (Monarthropalpus flavus) is one of the most destructive boxwood insect pests. First found in 1910, they can now be found anywhere boxwood grow in the United States. The eggs of this fly are laid inside the leaf where the larvae develop and feed on the tissue. This feeding results in blotchy, blistered leaves that swell, discolor, and can prematurely defoliate. The small, orange, mosquito-like fly emerge in late April or early May (in Virginia) and spend about 2 week mating and laying eggs. The larvae are the most destructive to the boxwood plant and they can feed from June through the early fall.
We are developing a site that can be used as a resource to help you understand this pest and how to manage it. For now, we recommend you look to the Saunders Brothers website for more information, linked below.