Tree and Shrub Pests

You won't see these small black weevils unless you go out with a light at nighttime. They cause classic notching damage on the edges of leaves.

Sawfly damage is done by larvae that resemble caterpillars. These insects feed in groups and can be found chewing the leaves of a variety of plants including roses, dogwoods, hibiscus, columbine, birch, and pines.

Needled evergreens are the preferred host of bagworms but don't be surprised to see the bags on the branches of shade trees.

If you see dead and wilted leaves on rhododendron, look at the stem below the damage for borer holes and prune out the damage.

Webbing on plants with stippled damage on foliage may indicate a spider mite infestation.

Psyllid insects produce a fluffy white waxy substance on boxwood plants. Leaves at the end of branches may appear cupped and distorted.

Be on the lookout for a new pest of boxwoods. Box tree moth caterpillars chew the leaves of boxwood plants and can cause complete defoliation. Boxwoods are their only host plant. This pest has been found in several US states, but it is not in Maryland yet (as of August 2024). If you find it, please report it to us.

Leafminers feed between the upper and lower surfaces of a leaf.

Armored scale insects are a large group of sucking insects that can be tricky to find, identify, and manage.

There are many scale insects that feed on plants. They are often overlooked because they are immobile but they can cause serious damage to all types of plants.