Knowledgebase
Emerald ash borer #926727
Asked March 25, 2026, 12:26 PM EDT
Greene County Ohio
Expert Response
Should we continue to treat our ash trees?
Hi Carol,
As long as there the emerald ash borer is detected in Greene County, you should continue to treat your ash trees. I am including several resources for you to review. To summarize the general thoughts: if you are doing the treatment yourself and are using soil drenches of insecticide, keep applying them yearly. The best time is from April 1 to May 15. https://extension.entm.purdue.edu/EAB/PDF/NABB_DecisionGuide.pdf.
If you are having the trees injected by a professional with Emamectin benzoate, protection can last up to three years before it needs to be repeated. Those injection should take place between mid-May and mid-June. https://extension.entm.purdue.edu/EAB/PDF/NC-IPM.pdf. Insecticide control options start on page 10 of the publication.
Please let me know if you have additional questions,
Sabine
