boxwood leafminer

The boxwood leafminer, Monarthropalpusi flavus (Schank), is a key pest of boxwood. There is one generation a year with the larvae overwintering in the mined tissue of the leaves. The larvae resume feeding in the spring. The adult emergence in the Pacific Northwest occurs in late April through May and is associated with the timing of bloom of weigela, Weigela florida, and ranges from 300 to 650 degree days. Adults emerge, mate, and the female lays eggs deep into the tissue on the underside of the boxwood leaves. The eggs hatch in about three weeks and the larvae begin to feed causing the mining damage. The Below are some useful links for further information on this insect.

Oregon State University boxwood leafminer fact sheet with regional information

Penn State's Woody Ornamental IPM: Boxwood leafminer fact sheet. Both html and pdf versions are available. Includes images, information on resistant varieties, and management.

North Carolina State University Extension: Boxwood leafminer fact sheet. This publication has nice images of the adult leafminer and useful chemical management information.

G. d’Eustachio and M.J. Raupp's article in the Journal of ArboricultureAPPLICATION OF SYSTEMIC INSECTICIDES
, has extremely useful information on this insect's phenology and degree day development as well as details on two separate chemical trials on management of these midges.

M.J. Raupp, I.H. Mars, G. d'Eustachio have also published useful info on boxwood leafminer in ISHS Acta Horticulturae 630, INTEGRATED APPROACHES FOR MANAGING THE BOXWOOD LEAFMINER, MONARTHROPALPUS FLAVUS. The abstract details additional work with particular emphasis on resistant cultivars.

S. Gill, P. Shrewsbury, both from the University of Maryland and J. Lutz, Joanne’s IPM, Inc. have also posted their work looking at chemical management of boxwood leafminer, Evaluation of Systemic Insecticides Imidacloprid and Thiamethoxam For Control of Boxwood leafminer

Original publication: 5/4/2006
Most recent update. 5/8/2013

Author: R.L. Rosetta, Extension Nursery Integrated Pest Management, Department of Horticulture, Oregon State University

Boxwood leafminer damage
Boxwood leafminer damage
Boxood leafminer damage

Photo: IPM images/John Weidhass
Boxwood leafminer damage on a branch
Boxwood leafminer damage
Boxwood leafminer larvae