The Emerald Ash Borer (EAB) is responsible for the death of hundreds of millions of ash trees in 30
states. Ash trees make up an integral part of our island’s forest system. Without ash, natural
processes and cultural activities are significantly or forever altered.
Over a decade ago, members of the Beaver Island Association board (BIA) reached out to Michigan
State University, state and federal agencies for guidance in protecting the island’s forests from EAB.
The ash trees are predominantly located on the eastern half of Beaver Island. The Nature
Conservancy’s Senior Scientist, Dave Ewert, identified that the transportation of infested firewood
from the mainland to be the biggest threat to the island’s ash species. Following the state’s quarantine
on the transportation of firewood being rescinded for the archipelago, the island’s townships enacted
a wood transportation ordinance which prohibited the movement of untreated wood to any of the
Each year for over a decade the BIA volunteers secured purple EAB traps with lures, made available
by the United States Department of Agriculture (USDA). For months the purple traps hung in strategic
locations collecting insects. In October of 2019, the Michigan Department of Agriculture and Rural
Development entomologists confirmed that the traps had captured multiple EAB throughout Beaver
Island and in Northcutt Bay, Garden Island. This EAB confirmation was a game changer for the
island’s ash trees.
Michigan first detected EAB in 2002 when the southern half of the state was witnessing the death of
the ash trees. Michigan spent the next decade researching and developing a strategy to control EAB.
The first line of defense was an attempt to keep the EAB off the island through a wood movement
quarantine. Failing that, The Beaver Island Archipelago used current research directed activities to
assist in controlling the emergence of the islands’ EAB. Multiple control efforts included: Signage
reminding travelers that untreated wood products are prohibited from movement around the islands.
Select ash trees were girdled to attract EAB and act as sink trees. These trees will be cut down this
winter. Four parasitoid or predator EAB species, known as keystone species in Asia for control for EAB,
were introduced in ash stands positive for EAB. The parasitoids were produced and supplied from the
United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS), Plant
Protection and Quarantine (PPQ) EAB Parasitoid Rearing Facility in Brighton, MI. Based on MSU,
USDA, and DNR Forestry recommendations, we obtained and introduced these small bio-control
warriors. The parasitoids seek out and kill EAB. If the parasitoid release is successful, BIA volunteers
will collect specimens in June of 2020. If the EAB numbers fall then these parasitoids decrease or
cease to exist. A dozen specimen trees were treated by an arborist with a chemical to again assist
with control of EAB. The chemical injections were made possible through St. James Township’s
invasive species budget.
BIA volunteers will continue this winter to engage federal, state, and regional organizations in efforts
to control the now present population of Emerald Ash Borers. The other alternative is to do nothing
and let the ash trees succumb to the ravages of an invasive species. BIA and many off-island
agencies believe the Beaver Island Archipelago has a fighting chance to preserve a viable ash tree
Contact Pam Grasmick for further information.