Emerald Ash Borer
Emerald Ash Borers (EAB) kill ash trees. EAB is one of the most significant exotic forest pests threatening Minnesota because it has the potential to cause extensive ash tree mortality according to the Minnesota Department of Natural Resources.
The following are links and publications to aid in education about this pest.
Emerald Ash Borer Program: Minnesota Department of Agriculture
Invasive Terrestrial Animals: Minnesota Department of Natural Resources
Minnesota Invasive Terrestrial Plants and Pests Center: University of Minnesota
What do the EAB traps look like?
The trap is a three-dimensional triangle or prism. It’s made out of thin, corrugated, purple plastic that has been coated with non-toxic glue on all three sides. The purple prisms are about 24 inches long and hang vertically in an ash tree or are secured to the trunk of a tree. To increase the attractiveness of the trap to the beetles, it is baited with a lure (Manuka oil).
Why is the color purple significant and what is the lure?
For many insects, color frequently plays an important role, and EAB is no exception. Scientists found that buprestids (the insect family to which EAB belongs) in general are more attracted to red and purple hues compared to other colors. Researchers initiated a study using a variety of red and purple traps to determine which trap attracted the most beetles; the purple trap achieved the best results. To improve the purple traps’ attractiveness to EAB adults, they are baited with oil from the Manuka tree. Researchers found that there are four active compounds in Manuka oil that are also produced when an ash tree is stressed. Researchers also discovered there was an EAB antennal response to these compounds. In field tests when baited traps and non-baited traps were compared, traps baited with Manuka oil attracted more beetles than traps that were not baited.
If a purple trap is in my area, does that mean EAB is there?
Purple traps help detect EAB. A trap located in your community does not mean EAB is present; it means we are looking for the beetle. The goals of the 2010 EAB Survey are to define the leading edge of the infested area and to locate new outlying EAB infestations.
Why are the purple traps only placed in ash trees?
Ash trees are the only host species for EAB. The life-cycle of EAB is dependent upon the ash tree; the adults feed on the leaves, lay eggs in its crevices, and the larvae develop under its bark. All ashes (green, white, black, etc.) are EAB hosts.
How long will the traps be in place?
The purple traps will be placed in ash trees beginning in June 2010. The traps will be monitored and remain in place throughout the summer during the beetles’ flight season and will be removed in the fall.
Is the purple trap safe?
The purple traps pose no risk to humans, pets, or wildlife; however, the non-toxic glue can be extremely sticky and messy if touched.
What should I do if I see a purple trap on the ground?
Please call the Northfield Streets and Parks Division at 507-645-3050
How does the purple trap work?
During EAB adult emergence, beetles fly around ash trees, nibbling on leaves and looking for a mate. If an EAB lands on a purple trap, it will get stuck in the glue. In the fall, crews will return to trap sites to collect samples and remove the traps.
What happens when an EAB is found on a purple trap?
The insect samples collected from the traps will be cleaned and sent to a USDA identifier for verification. All verification of EAB will be communicated to the appropriate State plant regulatory official.