Treating Ash Trees For Emerald Ash Borer

BUGS ARE HERE, It’s Time to Save Your Ash From the Emerald Ash Borer!


The Emerald Ash Borer (EAB) is an invasive pest introduced from Asia that attacks ash trees (Fraxinus spp.). This metallic wood-boring beetle was found in Detroit, Michigan and Ontario, Canada in 2002, and has continued to spread into neighboring states and eventually across the U.S. and Canada. 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. 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.

EAB 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 (epicormic) branches below the disrupted tissues. Dieback of the canopy is a symptom of EAB larval infestation; as many as one half of the branches may die back as infestation progresses. The bark will split over dead vascular tissues, and trees may die within only two years of the onset of symptoms.

Independent studies strongly recommend that treatments be applied early, before extensive disruption to the vascular tissues occurs. Dieback symptoms should be <40%. Arborjet recommends treatment when EAB is detected in your area, but trees still appear healthy for best outcomes. Treat ash with either IMA-jet (imidacloprid) or TREE-äge® Insecticide (emamectin benzoate) using the TREE I.V. system for high volume dosages or the QUIKjet micro-injector for lower volume applications. The comparatively large vasculature in ash trees will readily move IMA-jet upward into the canopy. TREE-äge is more viscous and will take slightly longer to inject but will provide a longer residual effect. TREE-äge and IMAjet will kill the EAB larvae inside the tree. See the IMA-jet and TREE-äge labels for dosage rate based on tree size. To give the tree a greater health benefit, a follow up application of ROOT-jet Iron or MIN-jet Iron is recommended, the specific formulation dependent upon soil type. When applied to the soil, ROOT-jet Iron supplies phosphorous, potassium, iron, manganese, and a low dose of nitrogen. MIN-jet Iron supplies both iron and manganese, micro-elements that may be sequestered in high pH soils, but essential to healthy, green foliage.