2008-10-09 / Local & State

The New Bug On The Block: Emerald Ash Borer

By Alex Surcica PROGRAM ASSISTANT, HORTICULTURE PENN STATE UNIVERSITY

The emerald Ash Borer (EAB) - Agrilus planipennis has an appetite capable of wiping out ash trees - Fraxinus spp. in the eastern two thirds of United States. An estimate from the U.S. Department of Agriculture indicates that there are 7 to 10 billion ash trees in North America. Due to human activities, the EAB has entered United States via Detroit, Mich., from Asia, most likely China. Discovered in 2002, the beetle has infested parts of Michigan, Illinois, Indiana, Maryland, Missouri, Ohio, Pennsylvania, Virginia, West Virginia and Wisconsin and killed millions of trees, leaving more than 40 million dead in Michigan alone. Currently in Pennsylvania, Mercer, Lawrence, Butler, Beaver and Allegheny counties are in quarantine. This restricts the movement from this area of: EAB in any stage of development; roots, stumps, branches, limbs or ash trees; nonconiferous firewood; chips larger than one inch; and any items made from or containing the wood of the ash tree that may spread EAB.

The adult emerald ash borer is metallic green, one-half inch long and one-eighth inch wide, and fits on a penny. Adults, which live for three weeks, begin to emerge from infested trees in mid-May, reach emergence peaks in late June to mid-July and cease activity in late August. The adults feed on ash leaves for two weeks, and can fly about half a mile away from their overwintering site. The females lay up to 90 eggs in bark crevices. After about two weeks the wormlike larvae hatch, tunnel in an "S" shape and feed under the bark throughout the fall. Depending upon the infestation size, this activity girdles and kills the tree in one to three years. Larvae overwinter as prepupae, and pupate in late spring. In temperate zones, the adults exit through oneeighth inch D-shaped holes the following May. In colder areas, the lifecycle of EAB can take up to three years.

The initial tree infestation with EAB is almost impossible to notice. Signs of infestation are dead branches in the upper part of the canopy, wild shoots growing out from the lower part of the trunk, unusually high woodpecker activity, one-eighth inch D-shaped holes and bark splits uncovering Sshaped tunnels. Current recommendations dictate that, once EAB infest a tree, it should to be removed, chipped and burned. This should be done only if knowledgeable personnel have identified the exotic beetle, since some native insects can look like EAB or have similar habits, but are not as detrimental. New insecticides, such as TreeAge, ImaJet, Arena, Merit 75, Safari and Xytect, are being tested and it appears that they can substantially slow the tree's decline once the exotic beetle attacks.

Because of its resilience, the ash tree has gained popularity in private and public landscapes, such as tree-lined streets and parks, especially after the Dutch elm disease ravages. Without considering the impacts on the biodiversity of our forests, EAB could pose a $20 billion threat to the economy, by affecting the logging, timber, nursery and landscape industries. For that reason, authorities and the public must place a great importance on stopping and eradicating this voracious pest. Some of the measures are as simple as burning the local firewood, planting locally produced nursery material, landscaping with a large diversity of trees, planting the right tree for a given spot, planting new trees correctly and taking care of existing trees by mulching them correctly.

Furthermore, one long-term goal we as a society should focus on is meeting our needs from the very place we live. Sourcing agricultural and natural resource products from nearby will substantially decrease the chances of importing more foreign pests and pathogens and will revitalize local economies. Presently, the United States is losing more than $100 billion yearly on attempting to control exotic introductions. Scientists say that these pests and pathogens could bring changes that will be even more radical to our environment than global warming.

For more information, please visit www.emeraldashborer.info/ or contact aps15@psu.edu"aps15@psu.edu.

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