Beech Scale and Hemlock Woolly Adelgid: Protecting Trees from These Invasive Pests

Jan 23 2017 - 2:00pm
Two serious invasive forest pests, beech scale and hemlock woolly adelgid, pose major risks to forest and landscape trees in Michigan.  Beech scale was found in Michigan in 2000 and now is distributed across much of the beech range in Upper and Lower Michigan.  This tiny insect, in combination with an invasive fungal pathogen, form the complex referred to as beech bark disease.  Beech bark disease leads to decline and eventual mortality of American beech trees, particularly large mature trees.  Controlling beech scale is difficult because of the white wax produced by the feeding scales.  Field trials in 2015-2016 have shown an insecticide and a non-toxic surfactant provided effective beech scale control.  Results of these studies and recommendations for using insecticides to protect landscape beech trees will be provided.  Localized infestations of hemlock woolly adelgid in western lower Michigan were found in 2015 and 2016. This insect is expected to lead to the decline and mortality of infested hemlocks of all size classes, usually within ten years. Systemic insecticides, however, provide effective control of HWA. This presentation will include a summary of HWA biology and impacts along with recommendations for using insecticide products to protect valuable trees.
Session Track: 
Turf & Landscape Management


Michigan State University

Deborah G. McCullough, a native of Flagstaff, Arizona, holds graduate degrees in Forestry (M.S., Northern Arizona University) and Entomology (Ph.D., University of Minnesota). She is a Professor with a joint appointment in the Dept. of Entomology and Dept. of Forestry at Michigan State University, with research, extension and teaching responsibilities. Dr. McCullough’s research focuses on the ecology, impacts and management of forest insects, including invasive pests such as emerald ash borer, beech bark disease, and most recently, hemlock woolly adelgid. She works with forest managers, regulatory officials, arborists and private landowners to develop sustainable management strategies to protect forests from damaging populations of forest insects. McCullough has published more than 100 papers about forest insect ecology and management in scientific journals, along with more than 200 extension bulletins and articles. She is a member of the national Forest Research Advisory Committee to USDA, the Michigan Interagency Forest Invasives Committee and frequently provides advice on forest insect management to state, municipal and private landowners.