Effects of Cutting Time, Stump Height, and Herbicide Application on Ash (Fraxinus Spp.) Stump Sprouting and Colonization by Emerald Ash Borer (Agrilus planipennis)

Abstract

Efforts to eradicate or slow the spread of emerald ash borer (EAB) (Agrilus planipennis Fairmaire [Coleoptera: Buprestidae]) include cutting infested and nearby uninfested ash (Fraxinus spp.) trees. However, ash trees readily sprout after they have been cut, providing potential host material for EAB. In 2004-2005, we conducted studies to determine how different cutting times (midspring, late spring, and late summer), different cutting heights (0-5, 10-15, and 20-25 cm above the ground), and triclopyr (44% active ingredient) stump treatment of green ash (Fraxinus pennsylvanica Marsh.) trees affected subsequent stump sprouting and colonization by EAB. We also cut white ash (Fraxinus americana L.) and black ash (Fraxinus nigra Marsh.) trees 20-25 cm above the ground in late spring. Some stumps of each ash species tested sprouted and were colonized by EAB. All green ash stumps treated with triclopyr died and were not colonized by EAB. Stump sprouting was significantly lower for stumps cut in late spring compared with stumps cut in midspring or late summer. Stump sprouting did not vary significantly among cutting heights. None of the green ash stumps cut in midspring or cut 0-5 cm above the ground were colonized by EAB; however, the frequency of stump colonization by EAB did not vary significantly among cutting times or cutting heights.