Boxwood Leafminer Fact Sheet

Conspicuous egg punctures in leaves.

Boxwood leafminer fact sheet. New leaves do not show signs of mining until late summer when the larvae are larger. Boxwood leafminer monarthropalpus flavus. The larvae of this fly feed on the tissue between the outer surfaces of the leaves. The adult leafminer is a yellow to orange red fly that looks like a mosquito.

Boxwood leafminer presence is indicated by blistering or irregularly shaped swellings on the leaves. The infested leaves appear blistered from late summer through the following spring. These flies are less than inch long and can often be seen swarming around boxwoods in the spring. This feeding results in blotch shaped mines in the boxwood leaves.

Mines are not evident for several weeks. When the boxwood s new growth appears in spring the females mate then insert their eggs into the underside of the leaves. The adult fly dies soon after. Infested leaves are spotted yellow and may drop prematurely.

Adult flies swarm around boxwoods about the time that the weigelas bloom. Blistering is most apparent on the undersides of the leaves and becomes most obvious late in the. Over the period of several years a lightly infested plant can become discolored brown and even defoliated. This is the most serious insect pest that attacks boxwood.

The leafminer is the larva immature form of a small orangish mosquito like fly. The boxwood leafminer continues to be the primary pest we deal with in boxwood. The good news about the boxwood leafminer is there are effective control options. Oval water soaked swellings on the lower leaf surface evident from midsummer until shed.