Controlling Boxwood Leafminer

Boxwood leafminer (Monarthropalpus flavus) is a serious pest in Franklin and Southfield that can wreak havoc on boxwood shrubs in your landscape. This tiny fly lays its eggs on boxwood leaves, and the larvae feed between the upper and lower leaf surfaces, causing unsightly damage and potentially weakening the plant.

The life cycle of the boxwood leafminer begins in spring when adult flies emerge from pupal cases inside the leaves. These orange-red flies, resembling small mosquitoes, swarm around boxwoods and mate. Females then insert their eggs into the undersides of new leaves. After hatching, the larvae (maggots) feed throughout the summer, creating characteristic blisters on the leaf undersides.

Symptoms of a boxwood leafminer infestation include:

• Yellow or brown blotches on leaves
• Puckered or blistered leaf undersides
• Smaller than normal boxwood leaves
• Overall unhealthy appearance of the plant

Owen Tree & Lawn Care recommends these strategies to control of boxwood leafminer:

1. Choose resistant cultivars for new planting areas
2. Encourage natural predators like green lacewings and spiders
3. Prune infested foliage before adult emergence in spring
4. Apply systemic insecticides to control the larvae that cannot be reached with foliar treatments

For organic control, consider using neem oil or Spinosad. If using chemical insecticides, options include bifenthrin, cyfluthrin, or imidacloprid. Owen Tree & Lawn Care has been successfully implementing these strategies in Franklin and Southfield. Maintaining overall plant health with insect control treatments and fertilization can protect your boxwoods from this persistent pest and keep your landscape looking its best.