This article was published in the Elsberry Democrat.
In the summer of 2002, an exotic beetle was discovered killing trees in the United States. The emerald ash borer, Agrilus planipennis, is native to eastern Asia, but was inadvertently transported in solid wood packing material to Michigan, probably sometime in the 1990’s. While the adults of this beetle only eat a small fraction of the available leaves, the immature larvae devour the inner bark of any and all ash trees. The S-shaped galleries of the pale green larvae girdle the trees and prevent them from moving water and nutrients through its vascular system. Within a few years of having been identified as infested, the crown of an attacked ash tree dies back.
Despite efforts to keep the infestation isolated, the beetle spread much faster than its estimated flight range suggested feasible. Humans unwittingly aided and continue to aid the beetle’s rapid spread throughout the Midwest and beyond. As people cut down their dead ash trees, the wood from those infested trees was taken by campers to distant locations to burn as firewood, and whatever wasn’t burned was left behind. Larvae eventually matured into the adult beetles, which emerged from the firewood to lay their eggs on the bark of ash trees in previously uninfested areas. In addition to being found in Ontario and Quebec, the emerald ash borer now has a range in the United States that goes from New Hampshire to Georgia to Colorado.
USDA and state quarantines are enacted in all areas where the emerald ash borer is known to be established. The entire state of Missouri is now under a federal quarantine for the movement of all non-coniferous firewood, and all ash trees and parts of ash trees. Compliance agreements are available with the USDA, and require that all ash wood be treated to kill the emerald ash borer larvae prior to moving out of the state. Ash trees are common now in landscape plantings throughout the United States, from small villages to large cities, and emerald ash borer infestations create enormous devastation and tree removal cost wherever they occur. Millions of dollars have been spent on dead ash tree removal and the emerald ash borer has not reached the full extent of the range of ash trees in North America.
What can the individual citizen do? First, when planting trees on individually owned property or in a community, always plant a variety of species, and never a monoculture. Many ash trees were planted to replace the American elm trees which were killed by Dutch elm disease. Second, always burn firewood where you buy it. Don’t transport firewood with on you a camping or hunting trip and leave potentially infested wood behind unburned. Third, keep an eye on your own ash trees for bark splits, D-shaped exit holes, and excessive woodpecker activity. Trees that are confirmed to have emerald ash borer should be taken down before they cause property damage or injure passerby. Specimen trees can be injected with insecticides to prevent them from becoming infested, but it must be repeated annually and it is not a cheap process.
Human activity brought this beautiful yet enormously destructive beetle to North America, and human activity has spread it so far so fast. Only education and a change in human behavior will slow its spread.
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