Aspenwall Tree Service, Inc. | Damaging Diseases and Pests


Aspenwall Tree Service, Inc. encourages a proactive approach to managing insect and diseases which begins with maintaining tree health using sound cultural practices including pruning and creating optimal soil conditions for tree growth. Periodic inspections are essential to detecting pest infestations before they reach damaging levels. We have over 25 years experience and are well trained to recognize threatening insects and diseases. We are happy to provide a FREE consultation to answer any questions you may have as well as provide advice on when treatments are necessary. Call, e-mail, or use the contact form below if you'd like to request your FREE consultation.

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Damaging Tree Diseases

Click on any name below to read more about these damaging diseases.

- Anthracnose
- Apple Scab
- Aspen Leaf Spot
- Cedar Apple Rust
- Diplodia Shoot Tip Blight
- Dothistroma Needle Blight
- Spruce Needle Drop


Anthracnose

Anthracnose

Anthracnose General Information

- Attacks Ash, Birch, Maple, Oak

Visual Signs and Symptoms

- Large tannish-brown, lesions occur in the spring on expanding leaflets, especially along margins and veins
- Leaves may become twisted and wrinkled
- Early leaf drop, particularly from the lower parts of the canopy

Protection and Prevention

- There is no cure for anthracnose once the infection has occurred, so protecting newly emerging foliage with a fungicide is the best preventative measure. Foliar sprays with fungicides are used in the spring as leaves are emerging and again 14-21 days later to prevent infection

Need more information? Contact us today!

Aspen Leaf Spot

Aspen Leaf Spot

Aspen Leaf Spot General Information

- Also known as Marssonina leaf spot
- Affects Aspen and Cottonwood in late Summer and Autumn
- Caused by a fungus
- Aspens are very sensitive to many pesticides, if applied incorrectly, leaves may turn black

Visual Signs and Symptoms

- Leaves affected with the disease will be scattered randomly throughout the tree and spots will appear randomly on the leaves
- The spots are dark brown to black circles containing rings

Protection and Prevention

- Rake fallen leaves in the Autumn to prevent the spread of the fungus
- Spray in the Spring when leaves are emerging from the bud

Need more information? Contact us today!

Diplodia Shoot Tip Blight

Diplodia Shoot Tip Blight

Diplodia Shoot Tip Blight General Information

- Affects Austrian, Scots, Ponderosa, and Mugo pine, spruce and fir
- Occurs most often in well established plantings; trees 25 to 30 years old can be especially vulnerable
- Wind and rain carry the spores to young needles and buds continuing its infection progression

Visual Signs and Symptoms

- Stunting and browning of current-year shoots in the lower branches
- Initially confined to the lower branches, progressing upward
- Stunted, straw-colored-to gray needles
- Small black dots at the base of needles and on cones

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Spruce Needle Drop
Spruce Needle Drop

Spruce Needle Drop General Information

- Affects Norway, white (Black Hills) and Colorado blue spruce trees

Visual Signs and Symptoms

- Yellowing and eventual browning of older needles
- Affected branches may be scattered through the canopy
- Frequently, by Autumn, all of the needles on the affected branches fall off except the newest needles on the tips of the branches

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Conifer Bark Beetle
Conifer Bark Beetle

Conifer Bark Beetle General Information

- Attack Pine and Spruce
- Primarily trees which are under stress, have been freshly killed or are in the process of dying
- Up to three generations per season may occur

Visual Signs and Symptoms

- Small white grubs with brown heads
- Brown or black beetles are usually small, up to 1/8"
- Small round holes in the bark (pupal cells)
- Tunnels and saw-dust shavings

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Emerald Ash Borer
Emerald Ash Borer

Emerald Ash Borer General Information

- Attacks any ash tree, regardless of age or condition
- Recognizable by the metallic green wings and purplish red abdomen on adult
- Originally discovered in southeastern Michigan in 2002, has killed over 20 million ash trees
- Travel long distances due to human activity, i.e. firewood
- Untreated trees die 4-6 years after initial infestation

Visual Signs and Symptoms

- Feeding galleries and larvae
- "D"-shaped exit holes
- Canopy dies from the top down
- Can take 2-3 years to become visually apparent

Protection and Prevention

- Pesticide treatment within 20 mile radius of infested area
- Tree-age® is applied by a system called micro-infusion
- The chemical is delivered directly into the tree's vasculary system
- Reduces the time between the treatment and full protection
- Currently labeled for 2 years of control

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Gypsy Moth
Gypsy Moth

Gypsy Moth General Information

- Known to feed on hundreds of plant species, the preferred include oak, aspen, willow, linden, hawthorn, apple and alder
- Young gyspy moth caterpillars are black with orange spots on their backs
- Mature caterpillars grow up to 2" long and have five pairs of blue spots and six pairs of red spots in rows across their backs
- Pupae are tear-drop shaped and brown

Visual Signs and Symptoms

- Holes in leaves, beginning in Spring, resulting in partial or complete defoliation by midsummer
- White, 1 ½ inches long, webby egg masses on trunks and limbs

Protection and Prevention

- Soil reatment and spray in Spring and early Summer

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Leafminer
Leafminer

Leafminer General Information

- Attack a variety of Birch
- Immature larvae feed individually between the leaf surfaces, creating kidney-shaped mines
- Larvae drop to the ground after about 2 weeks
- Adults emerge mid-June, lay eggs, larvae again feed for about two weeks
- The larvae drop into the soil, pupate and remain there until the following Spring

Visual Signs and Symptoms

- Kidney shaped mines
- Damage starts at the tops of trees and the ends of branches and progressively works down and inward

Protection and Prevention

- Soil injections and spray dependent upon stage

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Pine Needle Scale
Pine Needle Scale

Pine Needle Scale General Information

- Affects Arborvitae, Juniper, Cedar, Pine, Spruce
- Each female produces upwards to 100 eggs
- Two generations per year
- New crawlers emerge from under the scale covering of the parent scale and crawl a short distance or are windblown

Visual Signs and Symptoms

- White, waxy scale covering on the needles
- Red-colored eggs over-winter under the scale covering of the dead female on the needles
- Females will never develop legs, wings, eyes or antennae and never leave their waxy coverings
- Males gain the features of a typical adult insect body. Upon emergence, adult males will mate and then die

Protection and Prevention

- Rake fallen leaves in the Autumn to prevent the spread of the fungus
- Spray in the Spring when leaves are emerging from the bud

Need more information? Contact us today!

Spruce Gall
Spruce Gall

Spruce Gall General Information

- Galls are the unusual swellings at or near the end of the branches caused by the feeding of the insects called adelgids
- The two species, the Cooley and the Eastern, attack nearly all species of spruce and the Douglas fir
- Adults are 1-3 inches long and ½-¾ inches in diameter
- Females lay between 50 and 200 eggs that hatch in about 2 weeks, at which time they begin feeding

Visual Signs and Symptoms

- Galls caused by the Cooley adelgis are green or purple in color, begin forming in early spring and continue to grow until mid-summer, then they dry and turn brown
- Needles attached to the gall turn brown and die
- Galls caused by the Eastern adelgis resemble small pineapples and can reach up to 1½ inches in length and appear at the beginning of the current years growth as opposed to the end

Protection and Prevention

- Light infestations can be controlled by carefully pruning out the galls
- Spraying in the Spring, Summer and Fall, as each treatment has benefits and limitations

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Apple Scab

Apple Scab

Apple Scab General Information

- Affects all Malus species, including apple, fruit trees and flowering crabapples, and mountain ash
- The apple scab pathogen overwinters in infected leaves on the ground from the previous year. In spring, overwintered spores (ascospores) mature and are discharged over a period of 5 to 9 weeks. Wind and splashing rain carries apple scab spores from infected leaves to new growth on nearby trees where new infections begin
- In late Summer or early Fall, primary apple scab infections produce secondary spores and create new infections

Visual Signs and Symptoms

- Brown to olive, irregular-shaped spots on the leaves in late Spring
- Spots become dark and velvety in appearance
- Heavily infected leaves may become yellow and fall off the tree from late Spring through late Summer
- Fruit may also be infected by apple scab and display similar symptoms to those on leaves

Protection and Prevention

- Application of a fungicide in the spring as the leaves emerge. Proper timing of the application is crucical. Fungicides properly applied will be 95% effective for treating apple scab

Need more information? Contact us today!

Cedar Apple Rust

Cedar Apple Rust

Cedar Apple Rust General Information

- Affects Cedar and Crabapple
- CAR is a fungus

Visual Signs and Symptoms

- Rains cause horn-like structures, called telia, to extrude from galls
- In drier weather the telia turn brown
- Orange blisters on leaves
- Brown rust-like structres on leaves or fruit

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Dothistroma Needle Blight

Dothistroma Needle Blight

Dothistroma Needle Blight General Information

- Affects Larch and a wide variety of Pine
- This is a fungus

Visual Signs and Symptoms

- Deep green bands and yellow or tan spots on needles, progressing to the ends
- Infected needles drop late-Summer to Fall

Protection and Prevention

- Fungicides applied bi-annually in the growing season

Need more information? Contact us today!

Bronze Birch Borer
Bronze Birch Borer

Bronze Birch Borer General Information

- Attacks Birch Trees
- Recognizable by the metallic brown wings. However, the adults are rarely seen
- Found Newfoundland to British Columbia, south to Colorado, Idaho, Ohio, Oregon and West Virginia

Visual Signs and Symptoms

- "D"-shaped exit holes
- Larvae under the bark and feeding galleries
- Canopy dies from the top down

Protection and Prevention

- Mulching root zone and water during drought
- Minimize damage to root zone
- Application of pesticides

Need more information? Contact us today!

Eastern Tent Caterpillar
Eastern Tent Caterpillar

Eastern Tent Caterpillar General Information

- Attacks Prunus species such as cherry, plum, and peach, as well as flowering crabapple, hawthorn, and pear, maple, ash, birch, oak, willow, and poplar
- Eggs hatch in the spring at about the same time as leaf emergence on cherry
- Young larvae begin building their silken tents in a major branch fork or crotch for 6-8 weeks
- The pupal stage lasts for about three weeks. Adult moths emerge in early summer

Visual Signs and Symptoms

- Stripping of the foliage in late spring and early Summer
- A silky nest is visible in the crotches of branches
- Large numbers of dark colored larvae are visible both on the tree and in the nest

Protection and Prevention

- Removal of tents
- Removal of branches with tents
- Spring and Summer Soil Injections

Need more information? Contact us today!

Forest Tent Caterpillar
Forest Tent Caterpillar

Forest Tent Caterpillar General Information

- Hosts including aspen, oak, birch, ash, maple, elm, basswood, water tupelo, sweetgum, red alder, willow, and cherry
- Forest tent caterpillars have one generation per year
- Larvae emerge in mid-spring and the caterpillars feed for about 5-6 weeks
- In late spring and early summer, caterpillars move from feeding sites to protected area for their silky cocoons
- Approximately two weeks later, adult forest tent caterpillar moths emerge and lay shiny, black egg masses around small twigs

Visual Signs and Symptoms

- Stripping of foliage from mid spring to early summer
- Shiny black egg masses are often visible encircling twigs
- Young larvae are black, hairy and about 1/8 inch long, often visible in groups on twigs and trunks

Protection and Prevention

- Spring Soil Injection and Spray
- Most insecticides do not control these moth and butterfly insects

Need more information? Contact us today!

Japanese Beetle
Japanese Beetle

Japanese Beetle General Information

- Attack Lindens, Basswood, Willows, Birch and all fruit trees
- Attract more beetles while feeding, quickly causing severe

Visual Signs and Symptoms

- Skeletization of leaves

Protection and Prevention

- In pre- or early infestation treat with soil injections of Transect®
- In full infestation stage we recommend a spray application to kill the beetles. This has a 14-day residual effect
- Soil inject in early spring or Fall with Xytect® - causes beetles to dies after eating foliage
- Transect® and Xytect® are safe plant-based products

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Magnolia Scale
Magnolia Scale

Magnolia Scale General Information

- Affects Magnolia, Daphne, and Virginia Creeper
- Tiny, dark-colored nymphs - As scales grow they are often covered with a white, mealy wax
- In the Spring, the Scales begin to suck sap and have molted once by early May
- The males remain small, about 1/8-inch, and soon turn a translucent white and emerge as tiny, pink to yellow gnat- like insects with two long waxy threads extending from the tip of the abdomen
- The females continue to expand and by early June, they have turned a brownish-purple color. By July the females are covered with a powdery, white waxy coating and are shiny tannish brown and smooth, and may reach nearly ½ inch in diameter

Visual Signs and Symptoms

- Stunted growth
- Yellowish foliage, branch dieback or even the death of the plant
- Large quantities of a sugary excretion that build up on the tree’s leaves and twigs
- Sooty mold is a black fungus that grows on that honeydew and turns the covered leaves and twigs black

Protection and Prevention

- Rake fallen leaves in the Autumn to prevent the spread of the fungus
- Spray in the Spring when leaves are emerging from the bud

Need more information? Contact us today!

Pine Sawfly
Pine Sawfly

Pine Sawfly General Information

- Feed on the new growth of all pine species, favorites are Mugoa nd Austrian
- Most larvae are green or yellowish green in color with black, tan or orange head
- Adults are broad waist wasps
- Southwest typically attack open-grown trees or areas where pine is growing at a low density

Visual Signs and Symptoms

- Eggs are laid in slits cut in the edge of living pine needles

Protection and Prevention

- Timely spray with insecticides

Need more information? Contact us today!

Two-Lined Chestnut Borer
Two-Lined Chestnut Borer

Two-Lined Chestnut Borer General Information

- Attacks Oak and Chestnut Trees
- Recognizable by 2 thin, faint, white to golden-colored lines running down brown wings. However, the adults are rarely seen
- Found in eastern Canada, south to Georgia & Texas, and west to the Rockies

Visual Signs and Symptoms

- "D"-shaped exit holes
- Leaf wilting and dieback from the top of the tree downward
- Feeding galleries and larvae

Protection and Prevention

- Mulching root zone and water during drought
- Minimize damage to root zone
- Application of pesticides

Need more information? Contact us today!



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