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Learning Center

Tree & Shrub

Scale Insects

Scale insects are generally found on hardwoods and conifers. Some varieties are easily detected while others require expert identification. If you notice a sooty mold or ants on the tree (in large numbers), there is a possibility of an infection. Leaves turning yellow or red or abnormal growth at the point of the attack by the scale insect are clear signs. Heavy infestations will kill your tree.

Bag Worms

The bags start as very small silken containers on the underside of the stems on the trees and look like small pinecones. Most often bagworms infest Leyland Cypress, Japanese maple, and spruce. Some people simply pull the bag off and drop the bag into a container of soapy water. This is not the best way...when the bag is pulled off, there is a thread of the silk that holds the bagworm on the branch that is left behind. The silken thread will stay behind and will girdle the tip of the branch and will cause the tip to die off. The best way is to prevent bagworms from infesting your trees.  

Winter Injury

This is one of the more common problems facing trees and shrubs in our area that is caused by loss of moisture throughout the plant making them more susceptible to the harsh elements. Throughout the winter, your soil freezes, and the moisture becomes locked in and can not be accessed by your plant’s roots. We recommend the use of anti-desiccant sprays as one method to help your trees and shrubs survive the winter months.

Aphid Insects

This insect is often called a honey-dew. They secrete a sticky sap-like liquid that will coat sidewalks, cars, and patio furniture. These insects are small, pearl-shaped, soft-bodied bug with two cornicles (the cornicles are wax secreting). When plants are infested with aphids the leaves will yellow and often fall off the stems. The aphid collects in large numbers on the underside of leaves. Often a black sooty mold will develop on the stems of the plants.


Mites are not insects; they are spiders. They have eight legs and will usually be found on the underside of the leaves. Mites attach themselves using sucking mouthparts. Often mites are found on small evergreens and thrive in hot dry weather. Once the mites have grown in numbers, the damage can be seen easily as defoliation begins to occur quickly.

Anthracnose Disease

Dogwood trees in our area are highly susceptible to this disease. The first sign of anthracnose is spotting of the foliage in late spring and summer. Left unchecked, the dogwood will develop cankers on the branches. The cankers will girdle the tree and kill the dogwood. Most often this disease is found nearby to heavily wooded areas.

Borer Insects

Borers target weakened trees with heavy defoliation from tent caterpillars. Trees in decline tend to produce natural chemicals that will attract the borer. In this case, the best defense is a healthy tree. A tree properly maintained, fertilized, and pruned when appropriate, has a lesser chance of any borers invading.

Hemlock Woolly Adelgid

Hemlocks left untreated will die if there is an infection of the woolly adelgid. When a hemlock, generally a mature tree, has this insect there will a telltale sign: the branches will have what looks like an invasion of small cottony balls pasted to the underside of the twigs. This disease is easily controlled. Be on the lookout and call for professional help if you see “cotton ball” on the hemlock.

Lace Bugs

Where and what you plant does make a difference. Lace bugs prefer azalea, rhododendron, and andromeda. They like their host plants to be in full sun if at all possible and will grow to be about 3-4mm in length with wings that look lacy. The topsides of infected leaves will appear to have silver to yellow stippling while the underside of the leaf will black to brownish spots (looking something like a varnish). Lace bugs must be found early because there are no natural enemies to control the population and will become difficult to eliminate.

Tent Caterpillars

Tent caterpillars are very interesting insects with a voracious appetite for the leaves of ornamentals. We see the 'tents' in early spring, especially along our highways. There can be thousands of caterpillars within one tent. The caterpillars are bluish with a black head and a white strip down the center of the back. They cause defoliation which results in a weakened tree making it more susceptible to wood-boring insects.


Near the top of the worst insect list sits the weevil! Weevils have an elongated head and have a protruding curved snout that has the mouthparts and antenna. The weevil is nocturnal and causes damage in two major ways: damage to leaves that looks like notches (caused by mature weevils) and damage at or below the surface. At or below the surface the younger weevils, curved white legless grubs will girdle the roots. Once the roots of a plant have been girdled the plant will die because the plant will not be able to transport water. Adult weevils cannot fly and therefore the spread of weevils is not as quick as it could be. Weevils must be treated professionally.


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