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Summary
Got EAB In Your Ash Trees? Make a Diagnosis by Looking for These Signs and Symptoms (5/10/2009)
Emerald ash borer (EAB) has now been found in about half of Ohios 88 counties and is expected to spread even more. Whether you have one ash tree in your backyard or hundreds of them in your woodlot, its important to check your trees periodically to look for possible signs of an EAB infestation. An invasive, ash-munching insect originally from Asia, EAB typically kills trees within five years following the initial infestation. Only ash trees (those in the genus Fraxinus spp. such as green ash or black ash) are targeted by this pest. The mountain-ash (not a true ash despite its name) is not susceptible to EAB. The Ohio State University EAB Outreach Team has developed a detailed list of EAB signs and symptoms (including color pictures), which homeowners, woodland owners and tree-care professionals can use to help them monitor their ashes. This fact sheet is available at http://ashalert.osu.edu (look for Emerald Ash Borer Diagnostic Check-off List under the Factsheets/Bulletins section of the Web site) or through local OSU Extension offices. Outward evidence that ash trees may have fallen victim to EAB includes: Thinning canopy and top dieback, leading to the death of the tree within 2-4 years. Unusual epicormic shoots sprouting from the main trunk and/or from the base of the tree. Thin, relatively short (2-5 inches long) vertical splits through the bark of living trees. Unusually heavy woodpecker activity on living trees, particularly in the winter (woodpeckers like to feed on EAB larvae). Other symptoms of EAB infestation often require the bark be peeled off to detect them: D-shaped emergence holes through the bark, one-eighth of an inch in diameter. This symptom is very clear, as EAB exit holes are very distinct. If there is any doubt as to whether the holes are D-shaped, then it is not EAB. Exit holes of native borers are either round or oval and much larger in diameter (one-fourth of an inch or greater). S-shaped larval galleries under the bark that are tightly packed with fine frass (a mix of sawdust and excrement). They do not extend into the sapwood, as do those produced by the common native clearwing or roundheaded borers that also infest ash. Legless, flattened, heavily segmented, white to cream-colored larvae (1 inch in length when mature) found beneath the bark of living trees. Their long and narrow shape, flattened appearance, and distinct segmentation cause the larvae to resemble small tapeworms. The Ohio Department of Agriculture (ODA) should be notified at (888) OHIO-EAB if strong evidence of an EAB infestation has been found. Strong evidence means that signs and symptoms specific to EAB were observed, including D-shaped emergence holes and serpentine galleries under the bark. It is important to keep in mind that native ash borers are extremely common throughout the state, and that many borer-infested ash trees in Ohio are victims of these native insects. For additional information, see the Distinguishing EAB from Native Borers fact sheet at http://ashalert.osu.edu.
Emerald ash borer (EAB) has now been found in about half of Ohios 88 counties and is expected to spread even more. Whether you have one ash tree in your backyard or hundreds of them in your woodlot, its important to check your trees periodically to look for possible signs of an EAB infestation. An invasive, ash-munching insect originally from Asia, EAB typically kills trees within five years following the initial infestation. Only ash trees (those in the genus Fraxinus spp. such as green ash or black ash) are targeted by this pest. The mountain-ash (not a true ash despite its name) is not susceptible to EAB. The Ohio State University EAB Outreach Team has developed a detailed list of EAB signs and symptoms (including color pictures), which homeowners, woodland owners and tree-care professionals can use to help them monitor their ashes. This fact sheet is available at http://ashalert.osu.edu (look for Emerald Ash Borer Diagnostic Check-off List under the Factsheets/Bulletins section of the Web site) or through local OSU Extension offices. Outward evidence that ash trees may have fallen victim to EAB includes: Thinning canopy and top dieback, leading to the death of the tree within 2-4 years. Unusual epicormic shoots sprouting from the main trunk and/or from the base of the tree. Thin, relatively short (2-5 inches long) vertical splits through the bark of living trees. Unusually heavy woodpecker activity on living trees, particularly in the winter (woodpeckers like to feed on EAB larvae). Other symptoms of EAB infestation often require the bark be peeled off to detect them: D-shaped emergence holes through the bark, one-eighth of an inch in diameter. This symptom is very clear, as EAB exit holes are very distinct. If there is any doubt as to whether the holes are D-shaped, then it is not EAB. Exit holes of native borers are either round or oval and much larger in diameter (one-fourth of an inch or greater). S-shaped larval galleries under the bark that are tightly packed with fine frass (a mix of sawdust and excrement). They do not extend into the sapwood, as do those produced by the common native clearwing or roundheaded borers that also infest ash. Legless, flattened, heavily segmented, white to cream-colored larvae (1 inch in length when mature) found beneath the bark of living trees. Their long and narrow shape, flattened appearance, and distinct segmentation cause the larvae to resemble small tapeworms. The Ohio Department of Agriculture (ODA) should be notified at (888) OHIO-EAB if strong evidence of an EAB infestation has been found. Strong evidence means that signs and symptoms specific to EAB were observed, including D-shaped emergence holes and serpentine galleries under the bark. It is important to keep in mind that native ash borers are extremely common throughout the state, and that many borer-infested ash trees in Ohio are victims of these native insects. For additional information, see the Distinguishing EAB from Native Borers fact sheet at http://ashalert.osu.edu.
