Another Asian pest takes aim at Ohio trees

An invasive pest from Asia that threatens the health of another native tree can now be found from the southern tip of Ohio to its northern shore.

Infestations of hemlock woolly adelgid, a small, aphid-like insect, have now been discovered in Athens, Geauga and Lake counties, the Ohio Department of Agriculture and Ohio Department of Natural Resources announced Wednesday.

The insect feeds on the sap of eastern hemlocks found in Ohio and can cause the trees to lose needles and die. The pest also threatens the Carolina hemlock.

The hemlock-killing insect was first detected in Ohio in Miegs County 2012. HWA was discovered in Ohio’s southernmost Lawrence County in 2014. Ohio’s hemlock stands are primarily in the eastern half of the state.

Emerald ash borer, another invasive pest, was first discovered in Ohio in 2003. The beetle’s devastation has spread to all 88 counties of the state and has wiped out hundreds of millions of ash trees in North America.

Hemlock woolly adelgid, or HWA, was first reported in the eastern United States in 1951 near Richmond, Va., and is now established in parts of 20 states from Maine to Georgia, where infestations cover about half of the range of eastern hemlock, according to the state ag and natural resources departments. It is primarily transported by wind, birds and infested nursery stock.

The Ohio Department of Agriculture is moving to expand its hemlock quarantine to include Lake, Geauga and Athens counties, as well as Gallia County due to proximity. Ohio quarantine regulations restrict the movement of hemlock materials from counties known to be infested into non-infested Ohio counties.

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