Treating an emerald ash borer-infested tree is not cheap and can be ineffective at times. Most treatments cost between $12 and approximately $100 per tree, depending on its size. So far, treatments are only effective on slightly stressed or healthy trees. The treatments can kill off the bugs and larvae that are inside of the tree, but the tree will still be vulnerable to attacks, so the tree needs yearly treatment. Trees under 12 inches in diameter used to be treated with imidacloprid, an insecticide that is applied annually as a soil injection. However, the Naperville Park District switched to abamectin recently as researchers found that imidacloprid could be contributing to the collapse of bee colonies. Trees larger than 12 inches in diameter are treated with emamectin.
Abamectin is a more natural insecticide than most, made from fermented soil bacterium. It is injected annually into small plugs in the trunk of the tree, and is absorbed into the tree’s xylem, which then spreads it throughout the tree. When the emerald ash borer larvae begin to eat the xylem, it poisons them. However, if the xylem has already been eaten away when the abamectin is injected, it cannot be effectively circulated throughout the tree, leaving weak spots that the emerald ash borers can exploit. There are still problems regarding bees, even when using abamectin. However, they are much less serious. Imidacloprid was absorbed into the pollen of plants, which was then toxic to bees. Abamectin is extremely toxic to bees, but only in direct contact. The pollen does not absorb the insecticide. Currently various organizations are starting cross hybridization of American ash trees with stronger, less EAB-susceptible Asian ash trees in hopes of getting a more EAB-resistant tree. There have also been efforts to introduce natural predators to control the emerald ash borer population. In 2003 and 2004, the State of Michigan introduced four types of parasitic wasp that feed on emerald ash borers into their forests, three of those wasps being native species. However, the wasps only killed approximately 0.5% of ash borer larvae, and did not survive the winter. Since the completion of the study, another species of native parasitic wasp has been confirmed to prey upon emerald ash borers. Work is being done to develop rearing methods in hopes of the wasp being the solution to the infestation. |
This is an audio clip of Naperville Park District employee Tiffani Howell explaining how the ash borer treatments are applied.
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This website was developed by Daniel Josefchak and Ryan Malone.