treatment for borers on dogwwod trees

Asked May 22, 2015, 11:15 AM EDT

treatment for borers on dogwwod trees

Ross County Ohio

1 Response

Unfortunately, I need a bit more information than this! There are several borers that attack flowering dogwoods here in Ohio - dogwood clearwing borer, dogwood twig borer, dogwood Agrilus, Asian ambrosia beetles! Each borer would have a different recommendation for control. Usually, the dogwood clearwing borer is the one of concern, but we have seen a real increase in the ambrosia beetles and Agrilus borers. The clearwing borer is actually a caterpillar, so the most useful insecticides would be the systemics - dinotefuran (=Safari) or acetamiprid (=TriStar). These are the only neonicotinoid insecticides that have significant caterpillar killing ability. Safari is likely the easiest to apply by a homeowner as you can mix it up and simply drench the soil at the base of the infested plant. Dogwood clearwings are about to pupate, so an application now would waste the treatment. I would suggest making the application in mid-June to catch the next generation of larvae. TriStar is a bit more difficult to use as it has to be injected into the plant. Foliar sprays of either insecticide will not reach the clearwing borer larvae that are usually active near the root flair of infested trees.