Chemical treatments are available to help protect healthy Ash trees or those minimally affected. If you choose to use chemical protection, keep in mind that application must take place every two to three years, depending on the chemical and application method used, and can be somewhat expensive.
The decision to commit to long-term use of chemical protection is a private one, but some factors to consider are the relative importance and health of the tree or trees in your landscape and the affordability of a long-term commitment. As with all trees, Ash trees have multiple potential blights or diseases that will not be helped by EAB protection.
The City Forester recommends people with Ash trees contact a private arborist or tree care company to evaluate their options. He discourages the use of store-bought treatments that you spread on the ground to protect trees from Emerald Ash Borer. These may contaminate the surrounding soil and spread into groundwater or run off into nearby streams or drainages. They also can harm pollinators. Arborists inject trees directly, a method that is believed to have fewer concerns for water quality and is less likely to spread chemicals to water bodies, animals, insects or surrounding plants.