Pest Profile

Photo credit: Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org licensed under a Creative Commons Attribution 3.0 License.

Common Name: Holly Leafminer

Scientific Name: Phytomyza ilicicola

Order and Family: Diptera; Agromyzidae

Size and Appearance:

Length (mm) Appearance Egg - Laid within newly developing leaves

Larva/Nymph < 1.5 mm - Small, yellow maggot

Adult ~ 3 mm - Small, black fly

Pupa (if applicable) - Pupation occurs within leaf

Type of feeder (Chewing, sucking, etc.): Larvae have chewing mouthparts and adults have sponging mouthparts.

Host plant/s: American Holly, but will also attack English and Chinese hollies.

Description of Damage: Females flies will make small pinpoint holes in newly forming leaves known as “feeding punctures,” which both the males and females will use to feed on the leaf juices. After mating, the female will slit the undersides of newly developing leaves in order to oviposit her eggs within the leaf. Eggs create small raised bumps on the leaf. Once the eggs hatch they will create a mine within the leaf where the larvae will feed on leaf tissue until pupation. Mines or tunnels will have a yellowish or brown color. Leaves may also become distorted and flecked with tiny brown dots and eventually will die and fall to the ground.

References: Hoover, G. A. (2003, April). Native Holly Leafminer (Department of Entomology). Retrieved November 02, 2017, from http://ento.psu.edu/extension/factsheets/native-holly-leafminer

Missouri Botanical Garden. (n.d.). Holly leaf miner. Retrieved March 01, 2016, from http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home- gardener/advice-tips-resources/pests-and-problems/insects/flies/holly-leaf-miner.aspx