Boxwoods: Common Pests and How to Treat Them
Introduction
Boxwoods are popular shrubs that add beauty and structure to gardens. However, they can be susceptible to a variety of pests, including insects, nematodes, and diseases. Knowing how to identify and treat these pests is essential for maintaining healthy boxwoods.
Common Boxwood Pests
Boxwood Leafminer
The boxwood leafminer is a small fly that is the most damaging pest of boxwoods. The larvae of this fly feed on the inside of boxwood leaves, causing blisters and discoloration.
Treatment:
- Select resistant boxwood varieties.
- Prune before adult emergence or after eggs are laid.
- Apply insecticides containing bifenthrin, carbaryl, cyfluthrin, or malathion.
Boxwood Mite
The boxwood mite is a spider mite that feeds on the underside of boxwood leaves, causing them to become stippled with tiny white or yellow spots.
Treatment:
- Wash mites off with a stream of water.
- Apply horticultural oil.
- Use insecticides containing abamectin, bifenthrin, malathion, or oxythioquinox.
Boxwood Psyllid
The boxwood psyllid is an insect that damages boxwoods by causing leaves to cup and twig growth to be affected.
Treatment:
- Apply the same insecticides mentioned for boxwood mites in early May when the young have hatched.
Other Boxwood Pests
In addition to the three main pests mentioned above, boxwoods can also be affected by:
- Parasitic nematodes: Cause leaf bronzing, stunted growth, and decline.
- Scale: Sucking insects that cause marring on leaves.
- Mealybugs: Exude honeydew, which attracts ants.
- Whiteflies: Also sucking insects that cause damage to leaves.
- Caterpillars: May feed on boxwood leaves.
Preventing Boxwood Pests
There are several things you can do to prevent boxwood pests, including:
- Choose resistant boxwood varieties.
- Keep plants healthy with proper watering, fertilizing, and mulching.
- Inspect plants regularly for signs of pests.
- Remove any infested leaves or branches promptly.
- Avoid overwatering or overfertilizing, as this can attract pests.
Treating Boxwood Pests
If you do find pests on your boxwoods, there are a few things you can do to treat them:
- Insecticides: There are a variety of insecticides available to treat boxwood pests. Be sure to follow the instructions on the label carefully.
- Horticultural oil: Horticultural oil can be used to smother mites and other small pests.
- Neem oil: Neem oil is a natural insecticide that can be used to control a variety of pests.
- Predators and parasites: Ladybugs, lacewings, and other beneficial insects can help to control pests naturally.
Conclusion
Boxwoods are beautiful and versatile shrubs, but they can be susceptible to a variety of pests. By understanding how to identify and treat these pests, you can keep your boxwoods healthy and thriving.
