What is the SL.A.M. pilot project?
SL.A.M. stands for SL.owing A.sh M.ortality caused by emerald ash borer. Emerald ash borer (EAB) is an exotic beetle that is native to Asia. It was first found in southeast Michigan in 2002. Larvae (the immature stage of the beetle) feed under the bark of ash trees in tunnels called “galleries”. The galleries disrupt the ability of the tree to transport water and nutrients. This causes branches to die and eventually the entire tree succumbs. Emerald ash borer has become the most destructive forest insect to ever invade North America. Tens of millions of ash trees have been killed by EAB so far. Populations of EAB have been found in 14 states and 2 Canadian provinces. The goal of the SL.A.M. pilot project in Michigan’s Upper Peninsula is to delay and slow the expansion of ash mortality in outlier sites by reducing populations of the beetle.
Who is involved in the SL.A.M. pilot project?
The project includes cooperators from the USDA Forest Service, the USDA Animal and Plant Health Inspection Service (APHIS), Michigan State University (MSU), Michigan Technological University (MTU), the Michigan Dept. of Agriculture, the Michigan Dept. of Natural Resources and Environment, and two Conservation Districts in the Upper Peninsula.
How does SL.A.M work?
SLAM pilot projects are underway in Mackinac, Delta, Schoolcraft and Houghton counties in Michigan’s Upper Peninsula. These sites are intensively surveyed each year to identify the distribution of the EAB infestation. Scientists have developed several tools and options that may be used to manage EAB populations. Combinations of these tools are being evaluated in the SLAM pilot project to determine whether they can effectively slow the rate at which ash trees die.
The primary survey method used to delineate and monitor EAB populations involves girdled ash trees. Scientists have learned that EAB beetles are much more attracted to stressed ash trees than to healthy ash trees. Ash trees are girdled by removing a band of bark around the circumference of the tree trunk in spring. As the trees become stressed, the compounds emitted by ash leaves and bark change. EAB beetles detect and respond to these compounds. Beetles prefer to feed on the leaves of stressed ash trees. More importantly, female beetles are much more likely to lay eggs on stressed ash trees than on healthy ash trees. In fall, the girdled trees are felled and the bark is removed to see if EAB larvae are feeding on the tree. If larvae are present, they are counted and their developmental stage is determined. Scientists use data from girdled trees to evaluate the density and potential growth of the EAB population in the area.
In addition to girdled trees, purple “sticky” traps suspended in ash trees are also used for EAB surveys. The traps include lures that emit compounds similar to ash leaves and bark. The compounds may attract adult EAB beetles to the traps. The traps are placed in trees in the summer when EAB beetles begin flying, then removed late in the summer after the beetles are gone.
All the girdled detection trees and traps are identified by GPS coordinates. Maps are created by GIS specialists to illustrate the distribution of the EAB population in each site. Knowing where infested trees or positive traps are located helps the SLAM partners monitor the growth and spread of the EAB population and plan control activities.
Removing girdled ash trees in fall or winter kills the EAB larvae before they can develop into beetles and emerge the following summer. Some ash trees are treated with an insecticide that is injected directly into the tree. This controls adult EAB when they feed on the leaves of the tree and the larvae that may be feeding under the bark. Using a combination of girdled trees and insecticides should help slow the build-up of EAB populations and the progression of ash mortality.
What will happen after the survey?
Once the data from the girdled trees and traps are collected and processed, the approximate density and spread of EAB populations in a given area can be estimated and mapped. The annual growth and spread of the EAB population and the extent of ash mortality are compared to data from other EAB sites where no management has been attempted. Strategies are revised and refined to improve their effectiveness.
Results from the SLAM pilot projects in Upper Michigan will be shared with managers in other states such as Wisconsin, Minnesota, New York and Missouri, where EAB outlier sites have recently been found. While EAB will not be eradicated from Upper Michigan, learning how to slow the growth of EAB populations provides residents, foresters and arborists with time to develop long-term response and budget plans. In addition to the knowledge and experience gained, the SLAM pilot projects also provide employment for 36 people, most of whom are Upper Peninsula residents.
How is the SL.A.M. pilot project funded?
The project is funded in part by the USDA Forest Service, USDA APHIS and through the American Recovery and Reinvestment Act of 2009 (ARRA) grant.
How can I find out more about EAB?
Information about EAB can be found at www.emeraldashborer.info. This web site includes photos and helpful tips to identify ash trees and EAB, options for protecting ash trees, and links to information from other states with EAB infestations.