OZAUKEE COUNTY - The Emerald Ash Borer has killed millions of trees throughout the Midwest. How can you protect your trees? There are 700 million ash trees in Wisconsin. There's no way to give protective treatment to all those trees, but there are ways to protect the highly valued trees. It was never a matter of if the Emerald Ash Borer was coming to the state. It's always been a matter of when. We know the insects are in Ozaukee County, but tree experts expect they're other places, too. “Treatment is the best method and two years of treatment gives you pretty good protection before the tree becomes infested. So, we like to see two years of treatment before the insects get to our area,” Jesse Ziemienski from American Tree Experts said. Since the insects are already here, we don't have two years. Still, it’s recommended you protect your ash trees. American Tree Experts use Xytect insecticide to protect the trees. They dig around the base of the tree forming a small trench. “The amount of chemical used is based on diameter of the tree, which is absorbed through the roots of the tree and the chemical goes into the crown of the tree. The insect digests it and dies, but it works best as a preventative rather than curative,” Ziemienski said. That's because once the insect is in the tree, it is very difficult to eradicate it. The adult insects feed on the foliage. The larvae feed on the inner bark, preventing the tree from getting water and nutrients. “There are treatments available and there are individual treatments. It can be very costly,” Ziemienski said. American tree experts recommend you hire an expert but it can cost as much as $120 per tree and its only 85 percent effective. You can also go to garden centers and ask for products to protect ash trees. Click on the link under related content for more information on the Emerald Ash Borer.