June 30, 2013

Invasive pests need monitoring

An invasive species is one that is not native to an ecosystem and whose introduction can cause economic or environmental harm to that ecosystem or to public health. Once established, invasives may impact biodiversity by out-competing native species for food and habitat.

Both Emerald Ash Borer (EAB) and the Asian Longhorned Beetle (ALB) are native to Asia. Both are wood-boring insects, whose worm-like larvae develop beneath the bark or within the wood of live trees, leaving tunnels under the bark and emergence holes. One to two years of infestation can kill a healthy tree.

The adult EAB has metallic green wing covers and a coppery-colored abdomen. EABs are small, roughly 1/2 inch-long and 1/8 inch wide. Since they were initially discovered near Detroit, Mich., and across the Detroit River in Windsor, Ontario, in 2002, infestations have destroyed almost 100 million trees in more than 19 states. A worst-case scenario, in which all species of ash are wiped out across North America, remains a distinct possibility.

Infestations are known to exist in Albany, Cattaraugus, Dutchess, Erie, Genesee, Greene, Livingston, Monroe, Niagara, Orange, Steuben, Tioga and Ulster counties.

Currently, a quarantine is in effect in all or part of 42 New York counties restricting the movement of ash nursery stock, any part of ash trees, firewood from any species, wood chips and bark mulch from any tree larger than 1 inch in two dimensions and other items.

Possible symptoms of EAB include dieback of the upper and outer crown, epicormic sprouting at the base and/or on the main stem, vertical splits in the bark and woodpecker feeding.

Definite signs include D-shaped emergence holes, S-shaped larval galleries or the insect itself, larvae or adult.

ALB attacks many species of hardwood trees, among them maple, ash, birch, poplar, elm, horse chestnut and willow. The insect is already responsible for the loss of more than 80,000 trees in the United States. It should be considered a serious threat to the maple, wood products, nursery and tourism industries.

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