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As the larvae feed on the cambium, they create 'S'-shaped galleries in the wood. The galleries created from a large infestation weaken the ash trees causing canopy thinning and eventually canopy die-back. A secondary symptom is numerous shoots forming around the base of the ash tree.
|Current Map of Emerald Ash Borer Range|
"Systemic insecticides containing the active ingredients imidacloprid, dinotefuran or emamectin benzoate are commonly used to protect ash trees from EAB." (Potential Side Effects of EAB Insecticides) Imidacloprid belongs to the group of neonicotinoid insecticides which has been linked to Colony Collapse Disorder (CCD). Read a recent Xerces Society report here: Are Neonicotinoids Killing Bees? Today, a coalition of bee-keepers have filed a suit against the EPA for failing to suspend the use of neonicotinoid pesticides.
Imidacloprid, sold under the trade names Merit, Xytect, Optrol, ArmorTech, Enforce, Hawk-I, Turfthor, Malice, Premis, Criterion, Hunter, Submerge and Touchstone is typically applied as a soil drench or soil injection annually as a preventative treatment for emerald ash borer. For a homeowner with several ash trees, the cost can be very high. The city of Minneapolis now recommends replacing ash trees on residential properties rather than treating them due to the environmental risks from the treatments including, leaching into the surface or ground water, uptake by other plants visited by pollinators for nectar and pollen and non-target effects on woodpeckers feeding on EAB larvae.
Are your ash trees worth saving or should you be preparing for their replacement? Are the risks of using neonicotinoids too high? Purdue University offers a cost calculator for EAB treatment for homeowners here. Trees with structural defects, poorly sited, or with no historical or aesthetic value should not be treated. Read more guidelines here.
Perhaps our efforts should be focused on the conservation of ash tree species. Volunteers are needed for the collection of ash seeds to help preserve genetic variation and with a long-term goal of the reintroduction of ash trees into affected areas. Find out more information on how you can help collect ash tree seeds.
The Effects of Neonicotinoids on Honey and Bumble Bees.Vera Krischik, Entomology, University of Minnesota.
Chemicals Implicated. BeyondPesticides.org
Blacquiere, T., Smagghe, G., Van Gestel, C. A., & Mommaerts, V. (2012). Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment. Ecotoxicology, 1-20.
Emerald Ash Borer Info