Emerald ash borer treatment products for professionals

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Several insecticide products have worked well in research tests for control of emerald ash borer (EAB) in individual trees. At this time, treatments are needed every year for all the products in Table 1 with the exception of Tree-Äge which can be trunk-injected every other year. Tests have shown that we can protect healthy trees from emerald ash borer with insecticides, but successful protection of compromised trees is less likely. By the time you see canopy thinning, dead branches and woodpecker activity, the tree is already severely damaged, and it may be too late to save with insecticides. The most effective products appear to be working on trees with up to 50 percent canopy thinning, although the recovery from EAB damage is slow, with the trees looking a little better each year after treatment begins.

Imidacloprid basal soil injections or basal drenches should start when trees are still healthy (zero to 25 percent canopy thinning and dieback), because large trees (greater than 10-inches dbh) may not be protected well in the first year after basal soil drenches. Also, large trees should be watered during dry periods to maximize control with imidacloprid basal soil applications, and to maintain tree health.

Trunk injections and foliar sprays should also begin when trees still appear healthy. Some imidacloprid or bidrin trunk injection products have provided reliable control when treatments are made every year. Arborists should consider combining trunk injection treatments with a basal soil drench or foliar sprays for the first year or two when attempting to save trees that are already infested with EAB.
The products listed in the accompanying table will help protect trees from emerald ash borer if treatments begin when trees are still healthy. For more information on how well each of these products work, see reports of our research tests at http://emeraldashborer.info/. At the website, you will see a list of topics on the left side of your screen. Just click on research and you will find reports from at least five different EAB insecticide tests.

Table 1. List of products labeled for protecting ash trees from emerald ash borer.

Active Ingredient Product name Timing Type of Application
Imidacloprid Imicide (Mauget)
Pointer (Wedgle)
IMA-jet (Arborjet)
Merit Tree Injection
Late May to late June for control in current year. Trunk injection (once per year)
Emamectin   Tree-Age Late May to late June for control in current year. Trunk injection (once every two years)
Bidrin Injectacide-B Late May to early September Trunk injection (once per year)
Imidacloprid Merit April to early June High pressure basal soil injection (once) or basal soil drench
Dinotefuron  Safari Late May or June Trunk spray
Cyfluthrin     Tempo Early June and again in late June Trunk and foliage spray (twice)
Bifenthrin Onyx Early June and again in late June Trunk spray (twice)

Note: This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

Dr. Smitley’s work is funded in part by MSU‘s AgBioResearch.

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