Evaluation of Systemic Insecticides to Control Emerald Ash Borer
The emerald ash borer (EAB) is the most destructive invasive forest insect ever to have invaded North America. It has killed hundreds of millions of ash trees and threatens the entire ash resource. Injection of systemic insecticides is often a preferred method for controlling insect pests in landscapes because it eliminates potential spray drift thereby reducing applicator exposure and it minimizes impacts on non-target organisms.
We have conducted several studies evaluating the use of systemic insecticides to control EAB. Over the years, treatments have included trunk injection with imidacloprid (Imicide Mauget capsules), emamectin benzoate (TREEäge Arborjet tree-IV or quickjet), and azadirachtin products (TreeAzin and Azasol), and non-invasive bark sprays with imidacloprid (Macho 2) or dinotefuran (Safari) with or without the bark penetrating surfactant Pentra-Bark. We also tested the toxicity of these products to EAB larvae by incorporating various doses into artificial diet in the laboratory.
Insecticide efficacy was evaluated by collecting foliage to measure insecticide residue levels, conducting leaf feeding bioassays with adults fed foliage collected from control and treated trees, measuring larval density by removing sections of bark, and assessing canopy dieback. Larval toxicity was evaluated by periodically weighing larvae fed on treated and control artificial diet and examining larvae for mortality.
Evaluation of insecticide treatments will lead to recommendations that will enable arborists and landscapers to apply highly effective treatments. Results will also assist property owners, city arborists and landscapers in predicting treatment success and determining when treatment is not appropriate.
Overall, emamectin benzoate was found to be the most effective product and provided two to three years of nearly complete EAB control. All EAB adults fed leaves from trees treated with emamectin benzoate died within 4 days and larval densities were reduced by 99% compared to untreated trees. Dinotefuran and imidacloprid provided only 1 year of control and resulted in approximately 58-80% mortality of adults fed on leaves from treated trees and 57-68% reduction in larval densities within treated trees. Azadirachtin products were not toxic to EAB adults, but impair reproduction and control young larvae. All of the insecticides were toxic to EAB larvae fed treated artificial diet, but lethal concentrations and lethal time varied with insecticide. Time until 50% mortality was longer for imidacloprid and dinotefuran than for emamectin benzoate and the azadirachtin products.
Poland, Therese M.; Ciaramitaro, Tina M.; McCullough, Deborah G. 2016. Laboratory Evaluation of the Toxicity of Systemic Insecticides to Emerald Ash Borer Larvae. Journal of Economic Entomology. doi: 10.1093/jee/tov381
McCullough, Deborah G.; Poland, Therese M.; Anulewicz, Andrea C.; Lewis, Phillip; Cappaert, David. 2011. Evaluation of Agrilus planipennis (Coleoptera: Buprestidae) Control Provided by Emamectin Benzoate and Two Neonicotinoid Insecticides, One and Two Seasons After Treatment J. Econ. Entomol. 104(5): 1599Ð1612 (2011); DOI: http://dx.doi.org/10.1603/EC11101
- Therese Poland, US Forest Service - Northern Research Station Research Entomologist
- Deborah McCullough, Michigan State University
- Tina Ciaramitaro, US Forest Service - Northern Research Station Biological Sciences Technician
- David Cappaert, Michigan State University
- Andrea Anulewicz, Michigan State University
- Phil Lewis, APHIS
- John Molongoski, APHIS
Last Modified: 03/03/2016