The emerald ash borer (EAB) is a green beetle native to Eastern Russia and much of Asia. Outside of its
native region, it is an invasive species and is highly destructive to ash trees. EAB was first noted in
Michigan in 2002 and has since spread through the upper Midwest. It is believed to have been
introduced to North America through shipping crates/pallets from Asian sources. Currently (2015) the
EAB infestations have been found in Michigan, Ohio, Wisconsin, Minnesota, Ontario Canada, plus
perhaps another ten to fifteen states. Evidence suggests the EAB can spread between ten and twenty
miles per year. This spread is enhanced by transport of firewood and other wood products that contain
ash bark, which allows EAB to spread to new areas to create satellite populations outside of the main
infestation and quickly increase its range.
The EAB is almost totally destructive of native ash trees. After the initial infestation, all ash trees in the
area are expected to die within ten years without control measures. The ash species affected in
southeastern Minnesota include green ash, black ash, white ash, and blue ash. EAB seems to infect ash
trees in the order listed here; i.e., green and black first, then white, and finally blue ash.
Winona County is under a quarantine order issued by the United States Department of Agriculture
(USDA). The City of Lewiston is, therefore, also within an EAB infested area and subject to regulations of
the USDA. EAB will inevitably spread throughout the City and cause the loss of all ash trees.
The City of Lewiston needs to determine a course of action to address the EAB threat to its ash tree
population. This EAB Management Plan is written to outline Lewiston’s objectives and the methods to
be used in dealing with the impact of EAB on our ash trees. It is also to be used as a guide for City
administration and residents to follow with a high degree of confidence and order. The City will need to
create an EAB management budget to meet the costs of tree removal and/or treatment as well as public
education. This plan will address both public and private needs in an efficient and effective manner,
including replacement of removed trees with diversification of species and utilization of ash wood that is
removed. This plan, therefore, will lessen the social and economic impact from the impending EAB