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authors or has been consistently effective for EAB control. Please see the following sec- tions for specific information about results from these trials. Results of some tests have also been posted on www.emeraldashborer. info. Strategies for the most effective use of these insecticide products are described below. It is important to note that pesticide labels and registrations change constantly and vary from state to state. It is the legal responsibility of the pesticide applicator to read, understand and follow all current label directions for the specific pesticide product being used. Using Insecticides to Control EAB h:.(j i;l':~;:-:C,- '~::d~'s Systemic insecticides applied to the soil are taken up by the roots and translocated throughout the tree. The most widely tested soil-applied systemic insecticide for control of EAB is imidacloprid, which is available under several brand names for use by professional applicators and homeowners (see Table 1). All imidacloprid formulations can be applied as a drench by mixing the product with water, then pouring the solution directly on the soil around the base of the trunk. Dinotefuran was recently labeled for use against EAB as a soil treatment (in addition to its use as a basal trunk spray discussed beiow). Studies to test its effectiveness as a soil treatment are cur- rently underway in Michigan and Ohio. Imidacloprid soil applications should be made when the soil is moist but not satu- rated. Application to water-logged soil can result in poor uptake if the insecticide becomes excessively diluted and can aiso result in puddles of insecticide that could wash away, potentially contaminating surface waters and storm sewers. Insecticide uptake will also be limited when soil is excessively dry. Irrigating the soil surrounding the base of the tree before the insecticide application can improve uptake. The application rates for the homeowner product (Bayer Advanced'" Tree & Shrub Insect Control) and professional formulations -' of imidacloprid are very similar. Homeowners apply the same amount of active ingredient that professionals apply. However, there are certain restrictions on the use of homeowner formulations that do not apply to professional formulations. Homeowner formulations of imidacloprid can be applied only as a drench. It is not legal to inject these products into the soil, although some companies have mar- keted devices to homeowners specifically for this purpose. Homeowners are also restricted to making only one application per year. Several generic products containing imida- c10prid are available to homeowners, but the formulations vary and the effectiveness of these products has not yet been evaluated in university tests. Soil drenches offer the advantage of requir- ing no special equipment for applica- tion other than a bucket or watering can. However, imidacloprid can bind to surface layers of organic matter, such as mulch or leaf litter, which can reduce uptake by the tree. Before applying soil drenches, it is impor- tant to remove, rake or pull away any mulch or dead leaves so the insecticide solution is poured directly on the mineral soil. Imidacloprid formulations labeled for use by professionals can be applied as a soil drench or as soil injections. Soil injections require specialized equipment, but offer the advan- tage of placing the insecticide under mulch or turf and directly into the root zone. This also can help to prevent runoff on sloped surfaces. Injections should be made just deep enough to place the insecticide beneath the soil surface (2-4 inches). Soil injections should be made within 18 inches of the trunk where the density of fine roots is highest. As you move away from the tree, large radial roots diverge like spokes on a wheel and studies have shown that uptake is higher when the product is applied at the base of the trunk. There are no studies that show that applying fertilizer with imidacloprid enhances uptake or effectiveness of the insecticide. Optimal timing for imidacloprid soil injec- tions and drenches is mid-April to mid-May, depending on your region. Allow four to six weeks for uptake and distribution of the insecticide within the tree. In southern Ohio, for example, you would apply the product by INSECTICIDE OPTIONS FOR PROTECTING ASH TREES FROM EMERALD ASH BORER