Tree Pest Control

All About Pests, Diseases and Abiotic Disorders

The focus of Tree Huggerz Inc is always on the preservation of trees. In order to nurture their growth, longevity and vitality, an attentive Plant Health Care plan is essential. But even before that, a basic understanding of the common pests, diseases, and abiotic disorders affecting our local community will help get you started in the right direction. Use this page like an encyclopedia to help you recognize some of the most detrimental local threats to our trees and plants.

See anything that looks familiar to you? Perhaps you’ve seen it on your own property? Give us a call today! We’ll arrange for a Certified Plant Health Care Technician to visit your property for a formal diagnosis and then create a tailor-made wellness plan. Together, we can help cultivate a healthy canopy expanding over our beloved community for many years to come.

Man Spraying Tree with Pesticide Sprayer — Avondale, PA — Tree Huggerz Inc

Common Local Pests

Spotted Lanternfly

An invasive species native to China, Bangladesh and Vietnam. They were found in PA in 2014 and has since spread to 26 counties and counting. The Spotted Lanternfly (SLF) causes serious damage to trees through oozing sap, wilting, leaf curling, and of course, tree dieback. While feeding, the SLF excretes a sugary substance known as honeydew and encourages the growth of black sooty mold. A Lanternfly adult is approximately 1″ long and ½” wide at rest. The forewing is grey with black spots and the wing tips are reticulated black blocks outlined with grey. Hind wings bare contrasting color patterns of red and black with a white band. Its legs and head are black, but the abdomen is yellow with broad black bands. Immature stages have black with white spots and develop the red patches as they mature.

1st – 4th Instar Nymphs and Adult Female with Wings Spread Out

Photo courtesy: Lawrence Barringer, Pennsylvania Department of Agriculture

Lantern Fly Larvae Stages

A. Egg masses in egg cases

B. Lateral view of a resting adult

C. Adult congregation on a tree trunk and plant sap oozing from damaged area

Photo courtesy: Lawrence Barringer, Pennsylvania Department of Agriculture

Emerald Ash Borer

This insect is an invasive species from Asia. The larvae of the beetle destroy the vascular system of the tree causing dieback and death. Trees infested with the beetle have no natural defenses to the insect and will die within 3-5 years of the initial attack. Trees located in areas with a high bore population can die within as little as one year. By the time an ash tree shows obvious damage, it is usually too late to treat for EAB. Preventative treatment is the only method to protect and save your ash tree.

Phytophthora Root Rot

A soilborne water mold that spreads through the movement of water in the soil or on the surface, affecting conifers. New infections can occur when the temperatures exceed 59°F. Resting spores can survive for many years in the soil or plant and form during cold and/or dry periods. When required temperature and moisture conditions are present, resting spores germinate and form another type of spore-producing structure called a sporangia. 

When mature, numerous motile, infectious spores (Zoospores) are released. Zoospores are attracted to the plant roots by chemicals produced during growth. When they come in contact with susceptible tissue, they germinate, penetrate into the roots, form mycelium, and cause infection. As the mycelium continues to develop inside of the roots, the roots will die and turn brown. 

The fungus spreads from the outer roots toward the larger roots, the root crown, and eventually the stem. The conductive tissue of the plants will decay, preventing the flow of water and nutrients to the upper portion of the tree. Needles will first turn chlorotic and then a reddish brown, while branches wilt. The infection leads to death of the tree.

Bacterial Leaf Scorch (Oaks)

Leaf scorch, sometimes called marginal leaf burn, describes the death of tissue along the edge of the leaf. BLS can occur for a variety of reasons:

  • Insufficient moisture in the soil
  • Water loss happens rapidly, not allowing for adequate replenishment
  • Roots killed by plant pathogens, excavation, or compaction
  • Fungi/bacteria invade, stifling the water conducting vessels in the plant

In our neck of the woods, BLS is most readily seen in Oaks, but it’s also regularly seen in Red Maples, Elms, Sycamores, London Planes, Mulberries, and Dogwoods.

Hemlock Woolly Adelgid (Adelges Tsugae)

A tiny sap-sucking insect related to aphids, causing widespread death and decline of hemlock trees in the eastern United States. In its native range, HWA is not a serious pest because populations are managed by natural predators and parasitoids and by host resistance. Without these natural defenses, the adelgid poses a very serious threat to the sustainability of Eastern Hemlocks. The egg sacs of these insects look like the tips of cotton swabs clinging to the undersides of the current year’s hemlock twigs.

Lilac Borer

A clearwing moth with brown forewings and clear hind wings that closely resembles a paper wasp in form and behavior, although it cannot sting. Adults emerge in April and May to mate and the females lay their eggs on the rough bark or wounds of ash, lilac, and privet. As soon as they hatch, tiny worms bore into the bark. Most borer infestations occur in the lower portion of the host, from the soil line, up to 3 feet high. Ash trees are commonly attacked when they are small. Structural damage caused by the borers weakens the trees, making them highly susceptible to storm damage. Small, heavily attacked trees can result in total death.

Cherry Leaf Spot

Cherry leaf spot attacks the leaves, leaf stems, fruit, and fruit stems. The disease first emerges on upper sides of leaves as tiny, red to purple, circular spots. These enlarge to 1/8 to 1/4 inch in diameter and become red-brown to brown. By then, spots show brown on the undersides of leaves, and during wet periods tiny, whitish, feltlike patches appear in their centers. These contain the causal fungus spores. Some spots may drop out, leaving a shot-holed appearance. After the leaves become infected, they turn yellow and fall. The disease is most severe on leaves and may cause them to drop prematurely.

Shot Hole Disease

A serious fungal disease that creates BB sized holes in leaves, rough areas on fruit and concentric lesions on branches. During summer, infected leaves become chlorotic (yellow) and drop prematurely, often leaving the tree completely defoliated before fall in extremely wet years. Early defoliation impacts desired appearance and reduces flowering. Successive years of infection can reduce overall vitality, leading to other problems such as borer attacks, winter injury, and sunscald of the trunk.

Chlorosis

A yellowing of leaf tissue due to a lack of chlorophyll. Possible causes of chlorosis include poor drainage, damaged roots, compacted roots, high alkalinity and nutrient deficiencies in the plant. Nutrient deficiencies may occur because there is an insufficient amount in the soil or because the nutrients are unavailable due to a high pH (alkaline soil), or the nutrients may not be absorbed due to injured roots or poor root growth.

Soil Compaction

Soil compaction occurs when soil particles are pressed together, reducing pore space between them. Large pores are more effective at transporting water downward through the soil than smaller pores. Heavily compacted soils contain few large pores and less total pore volume resulting in greater density. Compacted soil has a reduced rate of both water infiltration and drainage. In addition, the exchange of gases slows down in compacted soils, causing an increase in the likelihood of aeration-related problems. Finally, while soil compaction increases soil strength, (the ability of soil to resist being moved by an applied force), a compacted soil also means roots must exert greater force to penetrate the compacted layer.

Diplodia Tip Blight

A common fungal disease of stressed conifers with needles in bunches of 2’s and 3’s, most frequently found in Pines. The fungus known as Diplodia sapinea targets new emerging growth leading to browning and die-back at branch tips. Symptoms often start on the lower half of the tree and progress upwards. When the new needles expand, they become stunted and turn yellow, then tan or brown. Generally, all needles on the current season’s shoot are killed. Loss of lower branches or full tree decline may occur, depending on the tree species and the severity of the infection.

Dothistroma Blight (Red-Band Needle Blight)

Red-band needle blight occurs throughout the growing season and during wet periods. Initial symptoms include dark green bands on the needles, quickly replaced with brown or reddish-brown lesions. After infection takes place, it may take 3-6 months for symptoms to become visible. In late summer, infected needles may show dark green bands that appear water soaked. This symptom occurs briefly and is usually not detected.

Next, yellow to tan spots become visible and then eventually become larger, reddish-brown lesions banding the needle. The fungus produces a toxin that quickly kills the tissue at the infection site and causes it to turn purplish red, giving this disease its common name, red-band needle blight. Girdling lesions will result in needle tips dying while the bases of the needles remain green. By late fall, tiny, black fruiting bodies may appear in the bands or dead tissue.

Girdling Roots

Lateral roots that are growing in a circular or spiral pattern around the trunk or below the soil line, cutting into at least one side of the main trunk and gradually strangling it. Trees and shrubs that are container-grown and pot-bound, frequently develop girdling roots. The pressure on the trunk caused by the girdling, restricts movement of water and vital nutrients. Affected trunks/stems will eventually become weakened and the tree becomes susceptible to fatality in five to fifteen years, whether from the girdling alone or in conjunction with environmental stresses, or insect/disease attack. Cultural practices like fertilization, irrigation, and pruning will not offset the slow growth caused by girdled roots. Once identified, they should be treated promptly.

Japanese Beetles

An invasive species that feeds on the leaves, flowers and fruit of more than 300 species of plants. They skeletonize leaves by feeding on tissue between the major veins giving them a lace-like appearance. Damaged leaves turn brown and may fall off.

Rhizosphaera Needle Cast

The most common disease affecting Spruce trees, but also infects several conifer species including; Fir, Cedar and Pine. Disease symptoms include a browning or purpling of needles, which eventually drop from the tree leaving bare patches. This symptom gives the disease its name “needle cast”. Typically, symptoms first appear on the lower branches of a tree and work from the inside of the tree out.

Weak Branch Unions

Weak branch unions are places where branches are not solidly attached to the tree. A weak union occurs when two or more similarly sized, usually upright branches, grow so closely together that bark grows between the branches, inside the union. This ingrown bark does not have the structural strength of wood and the union is much weaker than one that does not have included bark. The included bark may also act as a wedge and force the branch union to split apart. Trees with a tendency to form upright branches, such as elm and maple, often produce weak branch unions. Weak branch unions also form after a tree or branch is tipped or topped; when the main stem or a large branch, is cut at a right angle to the direction of growth leaving a large branch stub. The stub inevitably decays, providing very poor support for new epicormic branches that usually develop along the cut branch.

Cankers

Cankers are formed by the interaction between a host and pathogen. The pathogen grows within the wood and the host tree tries to contain the growth. Cankers can take months (or years) to enlarge enough to girdle twigs, branches, or trunks. These areas of trunk and/or branch tissues that have been killed by diseases, insects or non-living agents, (such as fire), become cankers, posing the same danger as a bark or wood crack. Cankers weaken the tree trunk or branch because the solid cylinder of sapwood strength has been broken. Decay is often associated with cankers. Cankers cause failures more often in younger tree trunks, as younger trunks are more supple and flexible. If there is a weak spot due to a canker, the tree trunk or branch is most likely to break at that point.

Cankers are usually oval to elongate but can vary considerably in size and shape. Typically, they appear as localized, sunken, slightly discolored, brown-to-reddish lesions on the bark of trunks and branches, or as injured areas on smaller twigs. The bark often splits between the diseased and the healthy tissue, and sometimes it may ooze sap or moisture. The inner bark turns black and sometimes gives off a foul odor. The newest leaves on affected branches are usually the first to show decline symptoms. Leaves may appear smaller than normal, pale green to yellow or brown, often curled and sparse. As the fungal pathogen invades bark and sapwood, the vascular system becomes blocked or dies, causing wilting and dieback to occur.

Winter Injury

Damage to/or death of foliage, roots, or limbs on trees and shrubs due to extreme fluctuations in temperature, damage from salt spray or damage from snow and ice.

Sooty Mold In Crape Myrtle

A fungal disease that grows on plants and other surfaces covered by honeydew, a sticky substance created by certain insects. Sooty mold’s name comes from the dark threadlike growth (mycelium) of the fungi resembling a layer of soot. Sooty mold is a frequent problem on the leaves of many evergreen shrubs including Azaleas, Camellias, Laurels, and Gardenias. It can also be a problem on deciduous trees and shrubs including Crepe Myrtles, Chinese Elms, Hollies, Silver Maples, or Sugarberries, or on plants growing beneath any of these plants. You may also see black sooty mold on walls, sidewalks, fences, automobiles, or almost anything else that has dropped from plants above them.

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For more information about our tree pest control services, or to schedule service and get a FREE estimate, call us at 610-606-1228.

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