Learning Center / Trees, shrubs and beds
What pests and diseases attack trees and shrubs here?
Scale, lace bugs, aphids, spider mites, leafminers and bagworms are the common pests; leaf spot, powdery mildew and winter burn are the common problems. Most are far easier to prevent than to rescue a plant from.
- By David Obeid, founder
- Reviewed
- 6 min read
What to look for
What are the signs of common tree and shrub problems?
These are the problems we see most on ornamental trees and shrubs in Northern Virginia.
| Problem | What you see | When |
|---|---|---|
| Scale insects | Small bumps on stems and leaves, sticky residue, black sooty mold. Crape myrtle scale is common here. | Through the season |
| Lace bugs | Speckled, bleached-looking leaves, especially on azaleas | Spring through summer |
| Aphids | Clusters of small insects on new growth, curled leaves, sticky residue | Spring and early summer |
| Spider mites | Fine stippling or bronzing on leaves, sometimes fine webbing | Hot, dry weather |
| Leafminers and sawflies | Winding trails inside leaves, or leaves chewed down to the veins | Spring and early summer |
| Bagworms | Small cone-shaped bags hanging from evergreens like arborvitae and juniper | Summer |
| Leaf spot and powdery mildew | Spotted leaves, or a white powdery coating | Humid summer weather |
| Winter burn | Browned edges and needles on evergreens by late winter | Winter |
Why prevention
Why treat before you see a problem?
Because an active infestation is rarely a one-and-done fix. It can take several seasons of treatment to bring a plant back, and some don't survive. Leaf spot and mildew are the same: preventive treatment in spring does far more than spraying once the leaves are already spotted.
Regular inspection catches pests early, when they are easiest to control.
How we handle it
What does a plant health care program do?
Our plant health care program is seven visits across the year, each one starting with an inspection, with treatment and fertilizer based on what your plants need. It runs from dormant oil for overwintering insects in late winter, through fungicide and insect control in the growing season, to an anti-desiccant against winter burn in late fall.
It starts at $107 a visit and covers ornamental trees and shrubs under 20 feet. Larger trees need a tree service.
Related questions
What people also ask
Can you save a plant that is already infested?
Sometimes. Suppressing an infestation is often a multi-year effort rather than a one-and-done treatment, and some plants do not survive.
What is winter burn?
Browning on evergreens caused by drying winds, winter sun and frozen soil pulling moisture out of the leaves and needles. An anti-desiccant applied in late fall helps prevent it.
Do you treat large trees?
The program focuses on ornamental trees and shrubs under 20 feet tall. Larger trees require specialized treatments.
Keep reading
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