Our trees are the unsung heroes of our yards. They are so solid and powerful, selflessly providing us with shade and other benefits, that we believe nothing can harm them.
Nevertheless, like all living things, trees are vulnerable to diseases and pests.
Let's take a look at the most common tree pests and diseases that can affect trees in the Woodstock area, so you know what to look for and how to best protect your trees from infection or infestation.
Signs and Symptoms of Common Native Tree Diseases in the South
Common tree diseases in the South aren't always easy to spot. They can slowly infect trees that are weak or vulnerable.
However, recognizing some classic visual cues can help you determine what is wrong with your tree. Detecting these symptoms can help you catch a problem before it becomes too dangerous to your tree's health.
Wilting is a classic sign of a tree problem.
Oak wilt is a common tree disease in the southern United States that causes this symptom. After all, this disease will be easily identified with the word "wilt" in its name.
Of course, all oak species are vulnerable. However, red oak species such as northern red, scarlet, and black oak are the most affected by oak wilt. White oaks are usually the least affected, including white, post, and chestnut oaks.
Oak wilt makes it hard to save trees that have already been infected. The best way to stop the disease from spreading is to cut back the roots of nearby susceptible trees and inject them with a systemic fungicide.
Spots on the leaves
Do you have lesions on your sycamores, oaks (mainly white oaks), maples, walnuts, or dogwood stems or leaves?
Anthracnose is a common tree disease in the South; these spots could be symptoms. If you let anthracnose infect your trees, the leaves and shoots can get sick, the leaves can fall off, and the twigs can die.
Pruning infected twigs and fertilizing properly and regularly can help reduce the impact of disease on shade and ornamental trees. Foliar sprays can treat leaves as they emerge in the spring.
Chlorosis causes leaves to turn yellowish instead of the usual vibrant green. Chlorosis can be detected on a few leaves, a single branch, half of your tree's crown, or the entire tree.
Phytophthora root rot is a common tree disease that can cause chlorosis symptoms. Many trees and shrubs are affected, such as azaleas, rhododendrons, Japanese hollies, boxwoods, hemlocks, mountain laurels, dogwoods, andromedas, firs, camellias, white pines, and yews.
If you notice tip dieback in your pine or spruce trees in the winter or early spring, it could be a sign of needle cast, specifically Rhizosphaera needle cast.
Needle cast is a common evergreen tree disease in the southern United States. Hemlocks and pines are particularly vulnerable in lowland areas. On the other hand, hemlocks, firs, and spruces are vulnerable in highland regions.
Diseases can grow faster in cool, wet weather or when leaves stay wet for a long time.
From mid- to late-summer, infected tree needles frequently turn yellow or have spots, and they then turn bright yellow, followed by brown. The needles are then frequently "cast." Infected needles that fall to the ground can produce spores that can blow away and infect other healthy trees.
To stop needle cast, cut off branches that are badly damaged, rake up and get rid of fallen needles, water deeply at the roots during droughts, and fertilize correctly to make the plant grow.
Have you noticed any premature leaf browning on your trees? This is called necrosis, and it could be a sign of a disease like bacterial leaf scorch in the tree.
The bacterium Xylella fastidiosa causes bacterial leaf scorch. It is commonly found in oaks, sycamores, red maples, sugar maples, silver maples, London planes, hackberries, mulberries, elms, and sweetgum trees.
To help your tree fight off this disease, try to reduce environmental stress by providing plenty of water when it's hot, sunny, and dry for an extended period. You can also mulch your tree to keep soil moisture in place, and regular fertilization can provide nutrients for your trees. If only a few branches are infected, trained local tree service professionals can prune them.
Early detection of this disease is critical for extending the life of your tree.
Common Native Tree Pests (Insects) Found in the South: Symptoms and Signs
Like most people, you probably dislike having insects in your home. That's how common tree pests feel when they chew, suckle, or bore into foliage or wood, weakening them and making them look bad.
Let's take a look at the most common signs and symptoms that insects leave on trees in the southern United States so you can spot any potential problems and save your trees.
The cankerworm is a chewing southern tree pest. Fruit trees, elms, ash, beech, hickories, maples, and oaks are among its hosts. Cankerworm larvae chew tree leaves, creating tiny holes in the leaves, and continue to feed until only the leaf veins remain.
These flat, gray, disc-like common tree insects are typically found on tree trunks or stems. This is the protective coating the pest uses to protect itself while laying eggs and hatching crawlers. Their mission is to infest. They stick their mouth parts, which look like straws, into the tree tissue and siphon out the insides.
Gloomy scales are common on maples, particularly red maples. If the pests are not visible, red maples will usually show signs of distress in the form of dying branches, yellowing leaves, black coloration on the trunk, and overall poor health.
Reduce environmental stress to keep your red maples happy and avoid gloomy scales. They prefer naturally moist areas, so there may be better places for a red maple than a hot, dry parking lot. Provide adequate deep watering to trees during a drought to avoid unnecessary stress and insect attack.
Spider mites and lace bugs are two common tree pests in the southern United States that cause stippling in your tree's leaves.
Both pests live on the undersides of leaves and are difficult to see with the naked eye. But the upper sides of the leaves look like they have dots, which shows that they are there.
Lace bugs and spider mites prefer a wide range of evergreen and deciduous trees. Azalea, andromeda, hawthorn, cotoneaster, quince, American elm, apple, sycamore, oak, and cherry are common lace bug favorites. Spider mites prefer coniferous evergreens such as azaleas, hollies, camellias, junipers, spruces, and arborvitae.
In the summer, spraying the bottoms of tree leaves with water may help to repel spider mites. There are also mite-specific pesticides, and dormant oils can eliminate spider mite eggs in the winter or before spring bud break.
Lace bugs can also be killed by putting horticultural oil on plants that are dormant and using pesticides when they are moving around. Start killing lace bugs with insecticides in the spring, between March and May, to avoid problems later in the season.
Almost everyone who lives in an area with oak trees has seen small balls dangling from tree branches. These are oak galls, which are deformed plants caused by gall-making insects like wasps or mites, which are common Southern tree pests. Galls are typically found on oak trees in the spring.
You can get rid of them by cutting off and destroying gall-infested twigs and branches, then crushing the galls to kill the developing larvae. Rake and remove gall-infested leaves. In the spring, well-timed pesticide applications can help break their life cycles.
While most galls do not harm tree health, many can distort leaves or cause early leaf drop. The only sure way to avoid galls is to select trees that do not harbor gall-producing insects or mites.
Borers (holes and frass)
The southern pine beetle is very good at chewing through the bark of your tree and leaving small, open holes that are easy to see.
It is the most damaging pine insect in the South and is voracious. During outbreaks, populations of this common tree pest can proliferate and kill many trees.
The southern pine beetle prefers loblolly, shortleaf, Virginia, pond, pitch, white, and Table Mountain pines over all other pine species. Longleaf pines are rarely attacked.
Your best bet for saving your southern pines is proactive prevention. Make a long-term plant care plan that includes methods for reducing environmental stress, such as fertilizing, mulching, pruning, and watering. Insecticide applications can help keep the southern pine beetle at bay in high-risk areas.
The ambrosia beetle is another common tree pest that likes to bore and tunnel into southern trees. This bug enjoys eating holes in trees such as crape myrtle, magnolia, oak, willow, peach, plum, cherry, Japanese maple, ash, dogwood, beech, and birch.
Ambrosia beetles prefer dying or dead trees. Unlike most bark beetles, Ambrosia beetles dig deep into trees to feed on the fungus they grow with the tree. They keep chewed wood, known as frass, out of their galleries by pushing it against the tree, allowing the ambrosia fungus to grow.
During the months when insects are most active, pyrethroid insecticides can help stop insect attacks. But insecticides can't kill beetles once they're inside a tree, so prevention is the best way to deal with this pest.
Do you believe these common pests are harming your trees?
Please contact our tree experts for advice on the next steps.