Tree And Shrub Problems
Atlanta Tree Diseases:
Many tree problems are caused by the action of one or more living organisms. Organisms which cause disease are called pathogens. The most common tree pathogens are fungi, a large and diverse group of plants lacking chlorophyll which derive their nourishment by parasitical green plants, thereby causing disease. Most fungi are microscopic, but a few, especially the wood-rotting fungi, produce large, often colorful, fruiting bodies as mushrooms or conks. Some tree diseases are also caused by bacteria and viruses.
Some types of pathogens infect many different tree species with similar disease symptoms. Other pathogens attack only a specific tree or only certain cultivars of a tree. If you have any trees near your home that have signs of rot or disease, do not wait to call! Dead, dying, or diseased trees will fall eventually, keep your family safe by hiring an Atlanta tree removal expert to inspect the trees around your home and give you a free estimate for the work that we suggest be done.
If you suspect that one of your trees is sick or damaged, check to see if it displays any of the following indicators of a tree in trouble:
- Mushroom-type fungi growing at the base of the tree
- Sawdust along the trunk base or root zone
- Cracks in the trunk or major limbs
- Hollow or decayed areas
- Wilted or discolored leaves
- Insect damage
- Dead branches
- Man-made wounds
Symptoms of Anthracnose vary according to the plant part and the host attacked. Leaf infections may show necrotic spots, irregular dead blotches or necrotic lesions associated with large leaf veins. Infections on new shoots may kill them entirely or cause severe tissue distortion. Defoliation may occur early in the season followed by a second growth of leaves in early summer. Buds are often invaded and killed. Buds are often invaded and killed. Twig lesion often expands and may girdle the twig entirely, causing death of the parts beyond the lesion. Repeated twig die back may alter the form of the tree, causing crooked branches and "witches brooms" (a development of clusters of twigs around a common point on a branch). Cankers form on the branches as a result of the death of buds and twigs. Cankers may remain active beyond one dormant season, girdling and killing branches. Cankers may also be inactivated by callus formation near the margins. Large trees that sustain repeated attacks by the pathogen are severely weakened showing loss of vigor, die back of large branches and increased susceptibility to borers and winter injury.
The disease is characterized by the presence of thick, black, irregular swellings on the twigs. The presence of these symptoms is often first noticed in the winter season when they are unobstructed by leaves. However, the fungal disease-causing agent has been present for quite some time. The pathogens present disrupts the normal growth of the twigs and a tumor like growth forms at the infection site. Infections may take place as much as a year or more prior to the development of these characteristic "knots", therefore, the swellings are normally not noticed until the winter of the second season of infection. It takes a keen observer to notice the subtle, initial symptoms present during the first season of infection. The first symptoms appear as small, light brown swellings of the current or previous seasons growth. By the next season the swellings turn olive green in color with a velvety texture. Over this growing season the knots darken and appear to have a hard, brittle texture. The hard, black knots are the typical symptoms associated with the disease. Knots vary in size from approximately 1-30cm (o.5 to 12 in) in length and from minute measurements to 5cm (2in) in circumference. The infected twigs often appear bent at the tips because of extra cellular growth on one side. Trees with heavy infections may contain numerous knots. Some of the older knots may appear white or pink in color. This discoloration is often seen in late summer and is caused by the fungal parasite Trichothecium Roseum.
Powdery mildew appears as a dusty white to gray coating over leaf surfaces or other plant parts. In most cases this fungal growth can be partially removed by rubbing the leaves. It might be identified incorrectly as dust that has accumulated on the leaves. Powdery mildew, however, will begin as discrete, usually circular, powdery white spots. As these spots expend they will coalesce, producing a continuous mat of mildew (similar to dirt or dust). A plant pathologist using a microscope can determine whether a fungus is present anytime the whitish patches are present. Symptoms usually appear late in the growing season on outdoor crops. The fungus is favored by periods of high humidity or site conditions that promote a more humid environment, such as close spacing of plants, densely growing plants, or shade. Indoors, symptoms may occur at anytime of year, but the rate of spread and development will be affected by the relative humidity and temperature. Injuries due to powdery mildews include; stunting and distortion of leaves, buds, growing tips, and fruit. The fungus may cause death of invaded tissue (begonia, for example). Yellowing of leaves and death of tissue may result in premature leaf drop. Nutrients are removed from the plant by the fungus during infection and may result in a general decline in the growth and vigor of the plant. The seriousness of the disease will depend on the extent of the various types of injury.
Honeydew is a sweet, clear, sticky substance secreted by insects such as aphids, mealy bugs, scale, and whiteflies. The honeydew drops from the insects to the leaves and twigs. Wind-blown sooty mold spores that stick to the honeydew then have a suitable medium for growth. When spores germinate, they send out black fungal strands (mycelia threads) that cover the plant tissue and cause discoloration. A heavy coat of black mold may build up on needles and twigs over more than one growing season. On leaves this coat of mold screens out light and reduces the plants capacity to produce food. On some trees no obvious damage can be noticed. Shrubs under trees that are heavily infested with honeydew producing insects may be seriously damaged or killed because the leaf chlorophyll can't function properly under the thick layer of sooty mold that develops. Azalea, Rhododendron, Pieris, Cotoneaster, Holly, and other low grounding shrubs growing under shady conditions are susceptible to serious damage.
Atlanta Tree and Shrub Insects:
Aphids are soft bodied insects that are capable of multiplying rapidly. The most distinguishing characteristics that they posses are their stylet-like mouthparts and a pair of tube like structures that project from their abdomen called cornicles. Aphids may be winged or wingless and they usually reproduce asexually, giving birth to live young through a process called parthenogenesis in which all the young are females. They grow by shedding their skin, which leaves a "ghost-like" skeleton on the leaf. Aphids feed by sucking plant juices.
The Japanese beetle is brilliantly colored, oval, and less than half an inch long. Wing colors are coppery with fine longitudinal lines, and the body is a beautiful metallic green. The five tufts of white hairs projecting from under the wing covers on each side and the two patches of white hairs at the tip of the abdomen are the distinguishing characteristics. More than 400 plant species within 95 families are susceptible to attack by this pest. Adult beetles not only damage numerous ornamental herbaceous plants, shrubs, vines and trees, but also small fruits, tree fruits, row crops and many other plants. Beetle grubs will attack turf (lawns, golf courses, and pastures) and the roots of many other crop and ornamental plants.
Lace bugs are small, broad, flat insects with clear, lacelike wings. Many small, black, varnish-like spots of excrement on the undersides of leaves and discolored foliage are evidence of lace bug infestation.
The female scales are brown or dark brown, pear shaped, and slightly over 1/16 inch long. The exuviae (first molted skin) is at the narrow end. Male scales are elongated, tiny and chaulky white in color with the exuviae at one end. As usual with armored scales, the actual body parts of the female is yellowish and sac-like with well development mouth parts but without legs, eyes, or antennae. The adult male is a small gnat-like insect. One symptom of a light attack is the occurrence of yellowish or whitish spots on the leaves. The female scales are usually found along the stems and leaf veins of the host plant. At times, however, the whole plant is "whitened" by the covers of the smaller male scales. When this occurs the plants leaves may drop and sometimes a normally green plant becomes bare by mid-summer. Heavily infested plants are usually killed if not treated. Plants growing close to buildings seem to be damaged more than those growing where there is free air circulation.
Spider mites, often called red spiders, are very small, barely visible to the naked eye. The newly hatched mite has 6 legs but all other active stages have 8 legs. They are related to spiders and ticks and are not insects. Some are reddish in color but others are brownish or pale green. Some have two or more darker spots on the back. Several common species spin fine, irregular webs over infested parts of plants but other species spin little or no webbing. Damage occurs when the mites suck plant juices with their small, needle-like mouthparts. Light infestations leave a pattern of small, pale spots on the infested plant. With heavier infestations the individual spots run together and can cause the death of the leaf or needle. This type of damage os often the only sign of an infestation in species which do not spin webs.
Adult whiteflies are small insects, approximately 1/16th inch (1.5 mm) in length, with four powdery white wings. When heavily infested plants are disturbed, one may notice a "cloud" of tiny white insects rising above it. The immature stages (eggs, crawlers, scales, and pupae) are all yellowish and found primarily on the underside of leaves. All stages of whiteflies feed on plant sap, using their piercing-sucking mouthparts, infested leaves can turn yellow and drop reducing plant vigor, but usually not killing the plant.