Ash borer prevention
I have some mature and large ash trees in my yard. I live just east of Waconia. Are there any preventive measures I can take to reduce the risk from Emerald Ash Borers? Thank you.
Carver County Minnesota
No native ash trees have resistance to Emerald ash borer. Measure the distance around the trunk (at 4.5 ft. above the ground) and divide it by three to get diameter at breast height. Use a soil drench containing 1.47% imidacloprid if the diameter at breast height is less than 20 inches. You should hire a certified arborist to treat trees over 20 inches at Breast Height. This site explains how to hire an arborist: http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/how-to-hire-a-professional-arborist/
It takes a while for fluids to transport the insecticide from the root of the tree to the leaves so it is best to treat trees in early spring April 1st and May 15th. Always follow all pesticide label directions. The following site will determine whether you should treat your ash trees.http://www.extension.umn.edu/garden/insects/find/emerald-ash-borer/docs/nabb-managing-eab-decision-guide.pdf