The Minnesota Dept. of Agriculture (MDA) held regional meetings around the state to update natural resource managers on the current status of Emerald Ash Borer (EAB). EAB was first found in Minnesota in May 2009, in Hennepin County. According to recent visual field surveys, biosurveillance, and branch sampling, Minnesota now has EAB confirmed in eleven counties; up from just seven counties as of December 2014. In addition, two isolated spots were confirmed at Park Point near Duluth. Across the United States, Louisiana is the newest state to confirm EAB in 2015.
MDA discussed their Bio-control strategy, which includes two species of parasitic wasps; one attacks the larval stage of EAB and the second the eggs. Wasps are generally released in natural areas, primarily along Mississippi River. In 2016, release will expand to natural forested areas that contain more than 25% ash trees. MDA views this method as a “long-term” strategy. Another control strategy is ash tree sanitation. Sanitation is the removal and processing of EAB infested ash trees and it aids in reducing EAB populations. Insecticides are an alternative to sanitation that give property owners the opportunity to save their ash trees. In addition, to these tactics, that directly reduce population of EAB, MDA is also implementing forest management practices to bolster the resilience of urban tree populations. For example, replacing poor value ash with other tree species and treating high value ash with insecticides.
Monitoring has allowed MDA to identify EAB infested trees. Branch sampling is the most sensitive way to monitor and can find the very early stages of an EAB infestation. Because of the high cost of this aggressive approach, MDA relies heavily on biosurveillance techniques. Wasp Watchers is a citizen surveillance project through U of M Extension, that engages volunteers in monitoring the activity of the Smoky Winged Beetle Bandit. This is a stingless, harmless wasp that specializes in hunting metallic wood boring beetles like EAB. For more information: http://z.umn.edu/waspwatchers or to get involved contact Jennifer Schultz 612-301-8310 or shultzj@umn.edu.
You may have seen or heard about purple traps hanging in trees. MDA has used them to assess how fast EAB spreads through a neighborhood. Visual assessment is a fast, cost effective way to detect potential EAB infested trees. Woodpecker activity is strongly correlated with presence of EAB within a tree. MDA considers trees with excessive wood pecks and sloughed off bark as possibly EAB positive and will then examine them closer to confirm diagnostic signs such as larvae, or “D” shaped exit holes left on the tree.
EAB has not yet been confirmed in Sherburne County. The Sherburne Soil and Water Conservation District (SWCD) has been working with each community in the County to increase the resilience of the urban tree populations. In 2015, the SWCD partnered with MDA to administer a survey and provided training to volunteers on conducting visual assessments. These survey efforts will be repeated in late winter 2016. Early detection is the most effective tool when it comes to minimizing the negative impact of EAB on Communities.
Movement of firewood remains the biggest contributor to the spread of EAB. Please remember to burn it where you buy it.
