Managing your ash trees affected by the emerald ash borer

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By Levi Berg

Hopefully by now, you have heard of the emerald ash borer (EAB). It is an invasive insect that is native to Asia, and has killed millions of ash trees throughout parts of the United States. The emerald ash borer is here, and has done an extensive amount of damage to our forests. 

You might think that this bug isn’t that bad, but the major concern is that our forests can contain up to 30 to 50 percent ash trees. The EAB is a serious threat to our forest, and unfortunately, it has hit most of our ash trees. 

There are certain insecticides that can be used on healthy ash trees that have not been infected with the emerald ash borer. However, certain insecticides only work with certain stages of the trees life. 

Smaller trees can use soil injections or drenches with either imidacloprid or dinotefuran. These soil drench insecticides can be purchased at some farm stores, but for larger trees, a truck injectable insecticides is warranted. 

Azadirachtin, imidacloprid and emamectin benzoate have been shown to be effective against the emerald ash borer, but may require a commercial pesticide applicator to treat your ash trees. Again, these insecticides only work with healthy ash trees that have not been extensively damaged by the emerald ash borer. 

Insecticides can help prevent EAB from entering and killing your ash trees, but make sure to follow the pesticide label instructions. 

Most insecticides will need to be administered more than just once. Most injectable insecticides will be effective for two years, but the soil drenches may need to be used multiple times in a year. Ultimately, insecticide treatments can be costly. If you are concerned about using insecticides, please contact a professional pesticide applicator for recommendations. 

Ash trees infected with the emerald ash borer are not likely to survive an attack, and precautions need to be taken for the dead/dying trees. Dead ash trees can cause serious damage to houses, vehicles and people. The wood of ash trees is brittle and after only a year or so large limbs can start falling out of your trees. 

Remove dead or dying trees to prevent the potential of dead limbs or falling trees from hurting people. 


Information was obtained from the “Insecticide Options for Protecting Ash Trees from Emerald Ash Borer.”