Michigan Department of Agriculture Completes Survey for Hemlock Woolly Adelgid

LANSING, MI - The Michigan Department of Agriculture (MDA) concluded
its intensive survey to detect Hemlock Woolly Adelgid (HWA), a serious
exotic and invasive forest pest in the northern Lower Peninsula.  MDA
inspected more than 20,000 hemlock trees growing on 4,300 acres in the
Petoskey area looking for signs of HWA.

“Despite regulatory and inspection efforts, the sheer volume of
plants and plant products commercially shipped into our state inevitably
results in the movement of plant pests,” says Don Koivisto, MDA
director.  “Strong early detection programs and aggressive responses
are required to insure the viability of Michigan’s forest and
agricultural ecosystems.”

The survey was part of a joint effort by MDA, the Michigan Department
of Natural Resources, and Michigan State University, after HWA was
confirmed at five locations in Harbor Springs in 2006 and 2007 (four in
2006, one in 2007).  Removal and destruction of infested hemlock,
multiple insecticide treatments of adjacent trees, and additional
detection efforts preceded the surveys completed this month.

Native to eastern Asia, the HWA was discovered in Virginia in 1951, and
has since spread to Georgia and Maine, decimating hemlock stands across
much of the eastern United States.  The Michigan infestations originated
from hemlock nursery stock grown in West Virginia and planted for
residential landscaping in Harbor Springs. 

“Hemlock Woolly Adelgid is a serious threat to our valuable forest
resource.  More than 100 million hemlock trees are present in
Michigan’s forests, providing valuable habitat for diverse
populations of animals such as birds, deer, and fish,” said Bob
Patterson, MDA Plant Pest Specialist.  “Continued surveys for this
pest are essential to prevent its permanent establishment in the
state.”

Adelgids are small, aphid-like insects that use their long, siphoning
mouthparts to extract sap from conifer trees.  In North America, the HWA
survives only on hemlock.  It gets its “woolly” name from the white,
cottony mass that covers its body and protects its eggs.

MDA has established quarantine against HWA to prevent the movement of
infested hemlock nursery stock and products into Michigan from infested
areas.  For more information about the HWA quarantine, please visit
MDA’s Web site at www.michigan.gov/mda.