Jeff from Prior Lake, Mn writes
Prevention is the key in ensuring your trees will not succumb to the emerald ash borer. Please contact your local extension office to check if you are in the risk zone for this pest. Depending on what region you're in will determine the best time of year to treat for Emerald Ash Borer. Adult EAB feed on ash foliage throughout their life span and females must feed on leaves for at least 14 days before they begin laying eggs. This provides a window of opportunity to control the adults before any new eggs or larvae are produced. The onset of adult beetle emergence begins from early May (southern Ohio) to early June (central Michigan) and peaks two to three weeks later. Beetle emergence may begin sooner at locales farther south or later in more northern areas. Soil drench treatments and soil injections around the base of the tree is the preferred method of treatment. Spraying the truck itself will not reach the insects underneath the bark. Using Merit 2F as a soil drench by mixing 0.1 to 0.2fl oz (3 to 6ml) per inch of trunk diameter. Soil Drench: Uniformally apply the dosage in no less than 10 gallons of water per 1000 square feet as a drench around the base of the tree, directed to the root zone. Remove plastic or any other barrier that will prevent the solution from reaching the root zone. Please refer to page 6 of the Merit 2F label for specific instructions. Two years of treatment in a row will need to be applied before this treatment can take its full effect. Soil injections and trunk injections are also viable options, but trunk injections risk damage to the tree if not done properly. Products containing bifenthrin, permethrin, or imidacloprid are good options and are found in many available insecticides. Please take a look at our Emerald Ash Borer Treatment Page for product recommendations and treatment procedures.
Answer last updated on: 10/12/2015