Protect Your Trees from Emerald Ash Borer EAB With Early Detection and Treatment

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Emerald Ash Borer is a destructive insect, first detected here in Boulder, CO in 2013. The City of Boulder is urging homeowners to act quickly if detecting trees that have been infected to help prevent an epidemic. The Emerald Ash Borer (EAB) is an invasive pest introduced from Asia that attacks ash trees. This metallic wood boring beetle was found in Detroit, Michigan and Ontario, Canada in 2002, and has moved across the U.S. and into Colorado. The adults typically emerge around June, leaving D-shaped exit holes in the bark. This ash tree insect briefly feeds in the canopy before reproducing and laying eggs in the twigs and branches. The adult is a small, metallic green beetle only 10-15 mm in length and about 3 mm in width. The larvae live under the bark of the tree and feed in the vascular cambium. Emerald Ash Borer larvae live under the bark and feed on the vascular tissues. Larvae create meandering galleries through the phloem, vascular cambium and etch the xylem, effectively girdling the tree. The tree responds by sprouting new branches below the disrupted tissues resulting in dieback of the canopy. As many as one half of the branches may die back as infestation progresses, this is one of the most visible and destructive symptoms of infestation. The bark will split over dead vascular tissues, and trees may die within only two years of the onset of symptoms, fortunately we have the ability to treat this beetle, unlike other rampant pest insects we have seen in Colorado. The treatment involves systemic insecticides containing the active ingredients imidacloprid, dinotefuran or emamectin benzoate are commonly used to protect ash trees from EAB. All three active ingredients are are registered for agricultural use and have been designated by the Environmental Protection Agency as Reduced-Risk insecticides for certain uses on food crops. This treatment can be applied in several forms including injections to the soil or directly into the base of the tree, and chemical spraying covering the bark of the branches and trunk of the tree. Imidacloprid is the leading ingreadient and most widely used insecticide globally. It has been utilized for many years to control pests of agricultural crops, as weed control in lawns and on landscape plants, this is the insecticide of choice for many application because of its low toxicity to mammals. This product is also used daily by homeowners to control fleas and ticks on pets. Dinotefuran is a relatively new product that has properties similar to those of imidacloprid, but it has not been researched as thoroughly. Emamectin benzoate, derived from a naturally occurring soil bacterium, has been registered for more than 10 years as a foliar spray to control pests in vegetable and cotton fields and parasitic sea lice in salmon aquaculture. Treatment delivered to the trunk includes injection of TreeAzin by BioForest Technologies, Inc. All other treatments are applied to the tree directly. All EAB treaaments are best used as a preventative before considerable damage has been done. This means homeowners need to be mindful of the health of their trees. If you intend to use the wood from trees cut down due to EAB, store and age the wood in the location you cut it down and away from other healthy trees as EAB larva may continue to emerge from the tree for up to two years. After two years you may store the wood anywhere safely. Contact a certified Arborist near you to assess the health of your Ash trees, treatment early on is more cost effective and helps prevent the spread of this damaging insect.