Friday, July 10, 2009

The Green Menance

We plagiarized the title from the United States Department of Agriculture (USDA) pamphlet on the Emerald Ash Borer (Agrilus planipennis).

From the USDA pamphlet: The Emerald Ash Borer (EAB) is a very small but very destructive beetle. Metallica green in color, its slender body measures 1/2-inch long and 1/8-inch wide. The average adult beetle can fit easily on a penny.

Native to China and eastern Asia, the EAB probably arrived in North America hidden in wood packing materials commonly used to ship consumer goods, auto parts, and other such products. Although no one can say for certain when the EAB arrived in southeastern Michigan, the scientific community now believes the beetle may have been present for up to 12 years before it was detected, based on its widespread distribution and destruction. The USDA officially identified the EAB in the summer of 2002.

This beetle is responsible for the death or decline of tens of millions of ash trees (Fraxinus spp.). As of December 2008, EABs have been detected in 10 states (Illinois, Indiana, Maryland, Michigan, Missouri, Ohio, Pennsylvania, Virginia, West Virginia, and Wisconsin) and parts of Canada. Although not suspected to be in South Carolina, the traps shown in the images have been placed near the nature center at Aububon's Francis Beidler Forest in order to detect the presence of EABs should they arrive.

Though the EABs method of arrival into the United States is unknown, the spread of EABs is well-documented. The artificial spread of the EAB is facilitated by humans moving common ash tree products such as firewood, nursery stock, green lumber, and chips. Some states are under full quarantine while others have quarantines in only portions of their state. Individuals face fines for moving ash products (mainly firewood) from quarantined areas. Firewood stacked for more than a year can still harbor EAB larvae and pose a risk for the spreading of the EAB.

Eggs laid in bark crevices hatch in about 10 days. The worm-like larvae then begin tunneling and feeding under the bark. This tunneling and feeding eventually girdles the tree cutting off the roots from the leaves...death of the tree is inevitable. Some native predators (woodpeckers and parasitic insects) have been seen attacking EABs, but their efforts have not been enough to slow the spread of the EAB or prevent the death of ash trees.

Previous blog entries on non-native species are "Save the Insects" and "Christmas Tree". More information on the Emerald Ash Borer can be found at the USDA Forest Service and USDA and Michigan DNR & Dept. of Agriculture.

Images by Mark Musselman

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