Last weekend I was unwrapping bark grafts and I discovered a graft union covered by a pile of nasty insect frass (photo at right). Looking closely at the grains of insect excrement, I found they were held together by fine silken threads. I pulled out my pocket knife to scrape off all the debris when I discovered a cream-colored larvae with a red head.
Dogwood borers seem to more of a problem in young, non-bearing orchards. Problems with this insect seem to disappear when trees begin nut production and a regular insecticide program is adopted to control nut feeding pests. Insecticides aimed at pecan nut casebearer and pecan weevil will serve to control both dogwood borer adults and emerging larvae.
Because I found extensive dogwood borer damage all across my young orchard, I will be applying a trunk spray of chlorpyrifos (Lorsban) to knock back the existing borer population. However, if I had been paying closer attention and recognized the borer threat earlier, an early May trunk spray would have been most effective.