Pest that kills hemlock found in Ohio


COLUMBUS — The Ohio Department of Agriculture and the Ohio Department of Natural Resources have discovered a hemlock-killing pest in Jackson County, in southern Ohio.

The Hemlock Woolly Adelgid is a small, aphid-like insect native to Asia that threatens the health of eastern hemlock and Carolina hemlock in the eastern United States.

HWA was first reported in the eastern United States in 1951 near Richmond, Virginia. Today, it is established in portions of 19 states from Maine to Georgia, where infestations cover about half of the range of eastern hemlock.

Ohio infestation

The most recent infestation was detected by ODNR officials at Lake Katharine State Nature Preserve in Jackson County. Officials have been conducting surveys around the infested area to determine the extent of the infestation. HWA is primarily transported by wind and birds. Officials believe the recent findings in Ohio are the result of natural spread from nearby areas where the pest is established.

There are now seven counties in Ohio where HWA has been detected in a naturally occurring stand of hemlock. In 2012, infestations were found in Meigs and Washington counties, in 2013, an infestation was detected in Hocking County, and in 2014, infestations were detected in Lawrence, Monroe and Vinton counties.

Quarantine expanded

At this time, ODA will move to expand its hemlock quarantine, enforced by ODA’s Plant Health Division, to include Jackson County. Ohio quarantine regulations restrict the movement of hemlock materials from counties known to be infested into non-infested Ohio counties.

Ohio’s quarantine law also requires hemlock materials grown in non-infested counties in quarantined states to be inspected before being shipped and have a phytosanitary certificate verifying that the plant material is free of HWA when entering Ohio.

For more information about the HWA in Ohio, visit


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