Boxwood Leafminer Fact Sheet

The adult fly dies soon after.

Boxwood leafminer fact sheet.

The larvae of this fly feed on the tissue between the outer surfaces of the leaves. This is the most serious insect pest that attacks boxwood. Boxwood leafminer presence is indicated by blistering or irregularly shaped swellings on the leaves. Boxwood leafminer is the most destructive insect pest of boxwood.

The leafminer is the larva immature form of a small orangish mosquito like fly. The adult leafminer is a yellow to orange red fly that looks like a mosquito. Adult flies swarm around boxwoods about the time that the weigelas bloom. These flies are less than inch long and can often be seen swarming around boxwoods in the spring.

Over the period of several years a lightly infested plant can become discolored brown and even defoliated. New leaves do not show signs of mining until late summer when the larvae are larger. This feeding results in blotch shaped mines in the boxwood leaves. Boxwood leafminer monarthropalpus flavus.

We have seen severe leafminer populations kill boxwood. The good news about the boxwood leafminer is there are effective control options. When the boxwood s new growth appears in spring the females mate then insert their eggs into the underside of the leaves. Mines are not evident for several weeks.

Oval water soaked swellings on the lower leaf surface evident from midsummer until shed. Infested leaves are spotted yellow and may drop prematurely. Blistering is most apparent on the undersides of the leaves and becomes most obvious late in the. Conspicuous egg punctures in leaves.