Tree & Shrub Health Problems
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.
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.
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.
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 tell tale 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.
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 lacey. 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.
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 by means of sucking mouth parts. 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.
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.
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 the 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 cause 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.
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.