The latest on EAB frequency of treatment

A recent conversation with a colleague revealed that there is still some confusion as to treatment frequency for Emerald Ash Borer, specifically with emamectin benzoate.

According to the 3rd Edition of Insecticide Options for Protecting Ash Trees from Emerald Ash Borer (excerpted):

“In several intensive studies conducted by MSU and OSU researchers at MSU, OSU, Morton Arboretum and Purdue, a single injection of emamectin benzoate (TREE-äge™) in mid-May or early June provided excellent control of EAB for up to three years, even during years of peak EAB densities”

“Two of the most recent studies have shown that even when TREE-äge™ is applied at the lowest rate on the label (0.1 g ai or 2.5 ml per DBH inch), trees are protected from EAB for three years. A six year MSU study quantified EAB larval densities on trees treated annually, at 2 year intervals or at 3 year intervals with a low (2.5 ml per DBH inch) or medium (5 ml per DBH inch) rate of TREE-age, dinotefuran basal trunk sprays or imidacloprid applied with Mauget capsules. Treated and untreated control trees were felled and debarked to assess efficacy. Results showed that both rates of TREE-äge provided nearly complete EAB control for three years post-treatment.”

“Biennial and annual TREE-äge injections, as well as annual basal trunk sprays of dinotefuran provided similarly high levels of control, while imidacloprid injections were less effective, even when applied annually. In other trials with side-by-side comparisons of insecticide products, emamectin benzoate has been consistently more effective than other systemic insecticides.”

In other words, it would seem the 3-year rotation is working very well for trees treated with emamectin benzoate. Annual dinotefuran treatments seem to be working well and imidacloprid not as much. This mirrors my own experience from the very beginning.