Various species of leaf miners attack boxwood, columbine, holly, and other perennials, as well as annual flowers and vegetables.
The name "leaf miners" is a catchall term for certain moth, beetle, and fly larvae that tunnel between the upper and lower surfaces of leaves.
Eggs are laid on the underside of immature leaves. Larvae from hatched eggs eat the leaf tissue between the upper and lower leaf surfaces, leaving behind a near-transparent trail in a characteristic pattern. If the affected leaf is torn in two, it can be seen that the leaf is hollow. After feeding, leaf miners drop off the leaf to pupate underground or under cover of plant debris.
Pick off and destroy infected leaves. Rotating crops and tilling the soil between crops helps destroy pupae. Parasitoid wasps, natural enemies of leaf miners, lay their eggs on larvae or near leaf miner egg sites. Pesticides can be effective if applied in mid-May before the much injury has occurred. There are at least two generations per year.