Top Ten Tree Problems
1. Lace Bugs
Lace bugs target broad-leaf evergreens such as Andromeda and Azalea. Lace bugs are usually detected when damage to the leaves of host plants becomes evident. The nymphs and adults live on the lower surface of leaves and suck juices through slender, piercing mouthparts. Look for yellow or whitish spots on the upper surface of the leaf. Plants that attract lace bugs should be monitored early in order to determine if an infestation is building. Elimination of the first generation of lace bugs is necessary if visual damage is to be avoided. Existing spotting and yellowing of leaves will not disappear once the lace bugs have been controlled.
Mites pose a serious threat to a wide variety of plants, from evergreens to many kinds of deciduous shade trees, such as elm, mountain ash, and oak. Damaged areas typically appear marked with many small, light flecks, giving the plant a somewhat speckled appearance. Mites favor warm, dry climates and are an extremely serious and common issue for homeowners.
Caterpillars do a lot of damage when they feed. Though their feeding may seem natural and innocuous, the defoliated host plants will suffer later in the growing season and beyond because of the effect on the plant's ability to perform normal photosynthesis. The plant will then have to expend an inordinate amount of energy re-foliating and consequently be much more vulnerable to disease and parasites. Without proper diagnosis and treatment, the plant could eventually die.
Borers are attracted to trees that have become unhealthy through neglect, normal aging or disease. Borers attack the weakened tree by burrowing in and laying eggs systemically in the trunk. Once infected, treatment to alleviate borers is problematic and is best controlled by a regular maintenance schedule to keep your trees healthy and unstressed.
5. Hemlock Woolly Adelgid
This is a common pest that gravitates towards aging trees, and if left untreated, can cause the death of these trees. Hemlock woolly adelgid sucks fluid from the base of hemlock needles. It may also inject toxins into the tree as it feeds, accelerating needle drop and branch dieback. Other factors can influence the impact of the hemlock woolly adelgid. Other insects, such as elongate hemlock scale, hemlock borer, and spittlebugs, which are also found on hemlock, can compound the impact of hemlock woolly adelgid.
6. Scale Insects
Scale insects are a peculiar group and look quite different from the typical insects we encounter day to day. Small, immobile, with no visible legs or antennae, they resemble individual fish scales pressed tightly against the plant on which they are feeding. Scale insects are common and are very serious pests of trees, shrubs, and indoor plants. Some common signs of an infestation are: abnormal leaf and shoot growth, yellow or red leaves, and branch gouting.
7. Anthracnose Disease
Anthracnose is a name for a group of diseases caused by several closely related fungi that attack many of our finest shade trees. It occurs most commonly and severely on sycamore, white oak, elm, dogwood, and maple. Other host plants that are usually only slightly affected include linden (basswood), tulip tree, hickory, birch, and walnut. Each species of anthracnose fungus attacks only a limited number of tree species. To identify Anthracnose disease, check for spotting on the foliage in the spring and the summer.
8. Aphid Insects
Aphids are sucking insects. Aphids are small, soft-bodied, pearl-shaped insects that have a pair of wax-secreting tubes projecting out from the fifth or sixth abdominal segment. Aphids are various colors including black, green, red, yellow, pink, white, brown, grayish, or lavender. An infestation typically causes yellow discoloration of the leaves and can lead to defoliation.
9. Weevil Insects
Commonly found on flowers and fruits, weevil infestation can be identified by unnatural notches found around the edges of the leaves.
10. Winter Injury
During the often cold, dry winter months, evergreen leaves and needles often lose moisture. When the ground is frozen, plants and trees cannot replenish moisture which ultimately leads to a “browning” or desiccated appearance. Anti-desiccants are applied in late fall to avoid this common plant and shrub condition.