University of Maryland Extension

Holly Leafminer - Trees and Shrubs

close up of holly leafminer damage
Damage to holly leaf caused by leafminers

Holly leafminers are small flies and there are several species of leaf miners that feed on holly: native holly leafminer (Phytomyza ilicicola) feeds mainly on American holly and the holly leaf- miner (Phytomyza ilicis) a European species. Damage is due mainly to the feeding of the minute yellow fly maggots. They feed by mining between the top and bottom surfaces of the leaves. The mines begin as narrow, inconspicuous tunnels. By fall, the mines look like irregular dark streaks. Adult females also cause injury by inserting their ovipositors into the leaves. Males and females feed on the juices that appear from the punctures. A large number of punctures in a leaf may cause a leaf to become stunted and twisted.

holly leafminer feeding damage
Adult females also cause injury by inserting their
ovipositors into the leaves. Males and females
feed on the juices that appear from the punctures.

Management

When possible American hollies should be grown in partial shade. Trees in full sun usually suffer more damage by this pest. The simplest way to control the holly leafminer is to pick off and destroy all infested leaves before May.

Additional Resource 

Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2019. Web Accessibility