Boxwood: Boxwood leafminer
categories: Boxwood Boxwood Insects Ornamentals Shrubs
revision date: 2023-04-04 12:00
Photo by: A.L. Antonelli
Biology
Leafminers feed by removing green tissue from between the upper and lower leaf surfaces. Feeding by leafminers can be detected by the presence of yellow to brownish blotch-like mines or by a blistered, thickened appearance of the leaves. The larval stage of the boxwood leafminer is a small yellow to green maggot found inside the mined leaves. The adult is a small (1/10″) orange to yellow fly which emerges in early May. Damage is mainly aesthetic, but repeated severe infestations may damage shrubs.
Management Options
Use Integrated Pest Management (IPM) for successful plant problem management.
Non-chemical Management
Select non-chemical management options as your first choice!
- Plant varieties of English boxwood (Buxus sempervirens) such as ‘Suffruticosa’, ‘Pendula’, and ‘Argenteo-varigata’, which are reported to be seldom damaged.
- Pinch to kill maggots in infested leaves when practical.
- Pick and destroy infested leaves when practical.
- Provide proper culture to maintain plant health. Healthy plants are more tolerant of insect damage.
- Natural predators may help control populations. Encourage predators such as green lacewings and spiders.
Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.
- If you choose to use a pesticide, apply when leaves are fully formed (around May 1st).
- Make a second application between mid-June and mid-July.
Approved Pesticides
Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.