Tree Damaging Insects
- Ash/Lilac Borer
- Distribution:This insect is distributed throughout southern Canada and the eastern United States westward to Saskatchewan and Utah and southward to Texas and Florida.
Hosts:The most common hosts of this insect are green and white ash Fraxinus spp and lilac Syringa spp. Other reported hosts are, European, Carolina, red and mountain ash, privet, and other plants of the family Oleaceae.
Damage:The larvae borer into the wood of the host plant creating holes in the trunk and main crotch area and swelling and cracking of the bark. The boring holes made by the larvae also create an entrance for secondary infestation by insects and disease organisms. Dieback or death of the host can occur if attacks are numerous enough
Control Tips: Plants should be maintained in good health and vigor to discourage infestation. Systemic insecticides are available to control infestations.
- Distribution:This insect is distributed throughout southern Canada and the eastern United States westward to Saskatchewan and Utah and southward to Texas and Florida.
- Asian Longhorned Beetle
- Distribution:native to China, Korea, and Japan. Active infestations in the United States are located in the eastern states and northeastern Illinois. Individual beetle sightings, without confirmed infestations, have also occurred in several other states.
Hosts:Most maple varieties, some ash, Hibiscus, Malus, Melia, Morus, populus, Prunus, Pyrus, Robinia, Salix, and Ulmus.
Damage:Due to the large size of the larvae, larvae tunneling severely weakens branches so that they break in the wind. Heavily infested trees eventually die. Since the borer affects healthy trees, as well as weakened and stressed trees, it is a major threat to both landscape and forest trees.
Control Tips:Strict sanitation is only known effective control. Repeated insecticide treatments within a large city setting are not considered a viable option for control of this pest. At this point in time, there are no effective insecticide treatment programs available.
- Distribution:native to China, Korea, and Japan. Active infestations in the United States are located in the eastern states and northeastern Illinois. Individual beetle sightings, without confirmed infestations, have also occurred in several other states.
- Bagworm
- Distribution:The bagworm is a widespread pest occurring from Atlantic states to the Mississippi Valley, west to Texas and Oklahoma.
Hosts: Practically all deciduous and evergreen shrubs and trees serve as suitable hosts for this pest. Particularly severe on junipers and arborvitae.
Damage: Damage to the host is done by larval feeding on the foliage. If enough larvae are present, plants can be stripped of foliage in a very short time. Plants are weakened and become vulnerable to attack by other insect and disease pests. Host plants may be killed by successive years of attack.
Control Tips: Chemical: apply a recommended insecticide in June or when the insect becomes active, to kill the larvae. Larvae are most easily controlled when young. Cultural and biological Control: Pick the bags off by hand and destroy them.
- Distribution:The bagworm is a widespread pest occurring from Atlantic states to the Mississippi Valley, west to Texas and Oklahoma.
- Dogwood Borer
- Distribution:This insect is distributed throughout Canada and eastern United States westward to the Mississippi Valley and southward to Texas and Florida.
Hosts: Include dogwood, oak, hickory, chestnut, cherry, apple, willow, beech, birch, and many other woody plants.
Damage: The larvae feed in the phloem and cambium of living wood. Infestation may result in lowered tree vitality, branch dieback, structural weakness or complete girdling and death of young trees. Trees may be disfigured and the galleries provide an entryway for secondary infestation by insects and disease organisms.
Control Tips: Plants should be maintained in good health and vigor to discourage infestation. Systemic insecticides and trunk sprays are available for control or prevention. Avoid damage to trunk from mowing equipment by keeping a ring of mulch to keep grass away from trunk.
- Distribution:This insect is distributed throughout Canada and eastern United States westward to the Mississippi Valley and southward to Texas and Florida.
- Eastern Tent Caterpillar
- Distribution:The eastern tent caterpillar is found throughout the eastern United States and Canada, and westward to the Rocky Mountains. This species may be localized in distribution in some areas. In Missouri, it is absent from the northwestern part of the state.
Hosts:Wild cherry, apple, hawthorn, and crabapple are the preferred hosts for feeding and oviposition, although this pest will feed to lesser degree on ash, birch, black gum, willow, maple, oak, poplar, peach, plum, witch hazel, beech, pear and rose.
Damage: During times when this pest is abundant, complete defoliation of the host trees occur. This may weaken the trees, although they are rarely killed or suffer permanent damage.
Control Tips: Webs may be removed from host trees in the spring by winding them upon the end of a pole having several nails driven into the end. This should be done at night or on a rainy day while the larvae are inside the webs, and the webs should then be burned. Insecticide sprays are useful in controlling the larvae when they are small. Sometimes natural enemies provide good control of this pest so that appreciable infestations so not usually occur in two successive years.
- Distribution:The eastern tent caterpillar is found throughout the eastern United States and Canada, and westward to the Rocky Mountains. This species may be localized in distribution in some areas. In Missouri, it is absent from the northwestern part of the state.
- Emerald Ash Borer
- Allen’s Tree Service offers systemic control and preventative of the Emerald Ash Borer. Please contact us for more information.
Scientists with the U.S. Department of Agriculture have discovered a beetle that decimates ash trees at a campground near Lake Wappapello near Poplar Bluff.
Recent tests confirm an infestation of Emerald Ash Borer at the U.S. Army Corps of Engineers lake.
The borer, a native of Asia, was first discovered near Detroit in 2002 and is responsible for killing millions of ash trees in Michigan. Infestations have been reported in eight other states including Illinois where it was found in 2006.
State and federal officials are currently surveying the area to determine the size of the infestation.
In other states where the borer has turned up, the transportation of firewood and trees sold in commercial nurseries have been restricted.
Distribution:The emerald ash borer is native to China, Japan, Korea, Mongolia and the far eastern portion of Russia. This species was unknown to American entomologists prior to 2002 when it was found attacking trees in southeast Michigan. In late July 2008, scientists confirmed a Missouri infestation of Emerald Ash Border at the U.S. Army corps of Engineers lake.
Hosts: In North America, the emerald ash borer is known only to attack ash species. Black ash, green ash, and white ash all have been found to be infested and killed by the insect. It is a very aggressive insect that kills healthy as well as weakened ash trees.
Damage: The larvae boring into the cambium and phloem rapidly damages infested ash trees. This damage disrupts the flow of water and nutrients and causes rapid decline of the tree. Infested trees will show thinning of the canopy during the initial phase of the infestation. Bark may split and peel off from areas where the larvae have damaged the vascular tissues underneath.
Control Tips: This is a quarantined pest subject to eradication efforts. Various insecticides are being tested for effectiveness in controlling larvae and adults.
- Allen’s Tree Service offers systemic control and preventative of the Emerald Ash Borer. Please contact us for more information.
- Euonymus Scale
- Distribution:The euonymus scale is widespread throughout the United States, except in the extreme north.
Hosts: All varieties of euonymus are attacked, though winged euonymus is least susceptible.
Damage:Feeding damage is caused by the piercing, sucking mourthparts of both nymphs and adults, and often results in leaf drop. Repeated defoliations can result in the death of the plant.
Control Tips: Prune heavily infested branches to the soil surface. Use a dormant treatment or a recommended insecticide to control crawlers in late May or June. Reapply as needed to control second generation crawlers. Control is probably impossible for Euonymus that has been heavily attacked and is in very poor health. Therefore, complete removal and destruction of the infected plants (including roots) is suggested.
- Distribution:The euonymus scale is widespread throughout the United States, except in the extreme north.
- Fall Webworm
- Distribution:This insect is native to North America and is distributed throughout most of the United States, southern Canada, and northern Mexico.
Hosts: In the United States, the fall webworm has been recorded on about 100 species of trees, and preferred hosts will differ from one region to the next. In the central part of the country, the preferred hosts include: walnut, hickory, persimmon, birch, cherry, crabapple and linden.
Damage: This species can cause severe defoliation of walnut and hickory. Feeding takes place within a silk web produced by the larvae. Webs are usually located terminally on branches and are enlarged and extended as fresh foliage is needed for food. Larvae do not totally consume the leaves but skeletonize them to such an extent that they curl up and die. This extensive webbing and heavy defoliation give affected trees a ragged, unhealthy appearance. Fortunately, the damage is done late in the growing season so that the long term health of the tree is not impaired.
Control Tips: On shade trees and shrubs, the webs of this pest may easily be removed by hand or burned out with a torch. Trees should be sprayed as soon as webs begin to appear, because after the webs become large, spray penetration may be difficult to achieve.
- Distribution:This insect is native to North America and is distributed throughout most of the United States, southern Canada, and northern Mexico.
- Forest Tent Caterpillar
- Distribution:This species is found throughout the greater part of the United States and Canada
Hosts: This insect feeds on a variety of trees including ash, birch, black gum, red gum, sugar maple, oak and poplar as the preferred hosts. It will feed on other species when preferred hosts are in short supply.
Damage: This species has been one of the most widespread defoliators of forest and shade trees throughout this range. Serious defoliation may occur for 3 to 5 years or more before natural environmental factors bring populations under control.
Control Tips: They may be destroyed by hand, or insecticides may be applied.
- Distribution:This species is found throughout the greater part of the United States and Canada
- Gypsy Moth
- Distribution:This species is found throughout the greater part of the United States and Canada
Hosts: This insect feeds on a variety of trees including ash, birch, black gum, red gum, sugar maple, oak and poplar as the preferred hosts. It will feed on other species when preferred hosts are in short supply.
Damage: This species has been one of the most widespread defoliators of forest and shade trees throughout this range. Serious defoliation may occur for 3 to 5 years or more before natural environmental factors bring populations under control.
Control Tips: They may be destroyed by hand, or insecticides may be applied.
- Distribution:This species is found throughout the greater part of the United States and Canada
- Japanese Beetle
- Distribution:Imported into New Jersey from Japan about 1916, the Japanese beetle has now spread to all states east of the Mississippi River except Florida and Wisconsin.
Hosts: together the adults and larvae feed on more than 300 species of plants. Ornamental trees, shrubs and sod make up the largest portion of host plants. Corn silks, a few weeds and wild grapes are also favored by the adults.
Damage: Adults damage plants by feeding on both foliage and blooms. If seen from a distance, heavily infested plants appear scorched. All leaf tissue between the veins is removed by the adults, so that the leaves look like brown lace.
Control Tips: Insecticide sprays can be used when the insects are identified.
- Distribution:Imported into New Jersey from Japan about 1916, the Japanese beetle has now spread to all states east of the Mississippi River except Florida and Wisconsin.
- Maple Bladdergall Mite
- Distribution:The maple bladdergall mite is a common pest of soft maples. Its range probably coincides with that of its host.
Hosts: This mite infests primarily red and silver maples.
Damage: Galls may become so numerous that the leaves become stunted and deformed. However, even in the most severe infestations there is no appreciable damage to the tree except to reduce its ornamental value.
Control Tips: Sprays are generally not recommended except with heavy infestations in order to protect the ornamental value of the tree.
- Distribution:The maple bladdergall mite is a common pest of soft maples. Its range probably coincides with that of its host.
- Mimosa Webworm
- Distribution:The mimosa webworm was introduced into the United States in 1940 from China. In past years, it has been found mainly in the east, south and Midwest, and it now occurs in California. This pest will probably eventually be found wherever its host plants occur.
Hosts: Although this pest was first recorded feeding on mimosa and does feed extensively on mimosa in the south, it feeds primarily on locust throughout much of its range, including Missouri and the central Midwest. Honeylocust, including the thornless cultivars, is the preferred host with Sunburst being the most susceptible. Moraine, Shademaster and Imperial appear to be more resistant, however all are subject to attack.
Damage: The larvae web leaflets together and feed within the protection of the web. They are gregarious and several larvae will be found within the large unsightly nest of webbing. In severe cases, webs may cover an entire tree, seriously detracting from the aesthetic value and beauty of the tree.
Control Tips: Because of the uniform nature of the webbing of this insect, control by hand picking is usually not feasible. However, chemical control is effective if sprays are applied while the larvae are small. Sprays should be repeated due to the overlapping generations during the summer months.
- Distribution:The mimosa webworm was introduced into the United States in 1940 from China. In past years, it has been found mainly in the east, south and Midwest, and it now occurs in California. This pest will probably eventually be found wherever its host plants occur.
- Oak Mite
- Distribution:Oak mites have been generally reported from the eastern United States as far west as Kansas.
Hosts: Chestnut, beech, birch, oak, elm, hickory, maple and other shade trees are infested; however, oak seems to be the preferred host.
Damage: Damage occurs to the upper leaf surfaces. Individual leaf cells are punctured and the cell sap is drawn out causing stippling of the foliage. Leaves appear grayish-tan or dusty. Damage to red oaks can be quite noticeable at a distance. Severe damage usually begins about mid-July and continues into August. Hot dry weather seems to favor mite development.
Control Tips:Control tips. If oak mite has been a problem a miticide should be used with some insecticides.
- Distribution:Oak mites have been generally reported from the eastern United States as far west as Kansas.
- Peachtree Borer
- Distribution:This species is distributed throughout the United States and Canada east of the Rocky Mountains wherever Prunus is found.
Hosts: This species develops in nearly all members of the genus Prunus, including peach, cultivated and wild cherry, plum, prune, nectarine, apricot and certain ornamental shrubs in the genus, such as flowering almond.
Damage: Larvae bore through the inner bark and sapwood of the trunk base and upper roots of living trees. Infestation results in lowered tree vitality, structural weakness, or complete girdling and death of young trees. Severely infested trees often break at the base in high winds. The galleries also provide an entry for secondary infestation by insects or disease organisms.
Control Tips: Like other wood borers, active infestations of this species are difficult to control by chemical means. Infestations may be chemically prevented by applying an insecticide that has some residual activity to the trunk base and surrounding leaf litter. To be effective, these applications must be timed critically to coincide with first egg hatch and reapplied during the hatching period before the previous application loses its residual activity. Infestations may be discouraged by keeping the plant healthy and vigorous, since weak plants are less able to defend against attack. Wounds are especially attractive attack points, avoid injury to the trunk with mowing or cultivating equipment.
- Distribution:This species is distributed throughout the United States and Canada east of the Rocky Mountains wherever Prunus is found.
- Pine Needle Scale
- Distribution:The pine needle scale occurs throughout the United States and southern Canada with some of the heaviest infestations occurring in the Midwest and eastern states.
Hosts: Nearly all species of pine and many species of spruce. The scale has also been observed on cedar, concolor fir, Douglas fir, and hemlock.
Damage: Heavy, prolonged, infestation of pine needle scale can cause plant mortality. Damage may also occur on only a single branch or branchlet. Pine needle scale may also weaken plants making them vulnerable to attack by other insects and diseases.
Control Tips: A dormant oil can be used or effective insecticide applications can be made when the red nymphs or crawlers are present from late April to May in Iowa.
- Distribution:The pine needle scale occurs throughout the United States and southern Canada with some of the heaviest infestations occurring in the Midwest and eastern states.
- Spruce Spider Mite
- Distribution:The Spruce Spider mite occurs worldwide in temperate climates.
Hosts: Most species of conifers are susceptible to the Spruce Spider mite. The most commonly listed hosts are Spruce, Arborvitae, juniper, Hemlock, Pines, Fir, Larch, Cedar, Japanese Cedar and Sequoia.
Damage: The damage is done by the piercing-sucking mouthparts, that puncture and suck out the cellular contents of the needles. The characteristic damage is a stippling or flecking or bleaching of the foliage. Typically Spruce turn grayish-brownish, Arborvitae turns brownish, Junipers yellow, and Hemlock nearly white. Weakened trees may be more susceptible to damage. Spider mite injury if often reported worse in hot, dry seasons, and in dry, dusty conditions. Also severe damage is often reported after broad-spectrum insecticides are used on conifers. Varietal susceptibility is also important, as Alberta dwarf Spruce and Savin Juniper are often damaged. Flecked, bleached, chlorotic or off-color coniferous foliage does not always mean spider mite damage. Oxidant pollution damage such as smog or ozone can be very similar to mite damage. Some weed killers might cause chlorosis of foliage. Low temperature desiccation or freeze injury resulting in browning out of second year needles can look similar to Spruce Spider Mite damage.
- Distribution:The Spruce Spider mite occurs worldwide in temperate climates.