Quaking Aspen Borer
This photo shows damage to a Quaking Aspen in Boise. Once the Boer has entered the heartwood, there is little to no control of this insect or any insect for that manner. Your best solution is to apply Ferti-lome 'Tree & Shrub' Insect Control prior to seeing insect damage. This product will last one-year from application date when applied according to directions.
Although you can apply Ferti-lome 'Tree & Shrub' Insect Control most any time of year, fall is an excellent time since the chemical is taken down into the root system and stored until spring. As the weather warms and the sap starts flowing, it takes the chemical back into the cambium and kills any insect that penetrates this layer of the plant.
For directions on how to apply or any other gardening question, please stop by our nursery or give us a call at 208.917.4820. We have been diagnosing problems in the landscape for over 44 years and we have an Idaho Certified Nurseryman on staff to answer all your gardening questions.