Range Expansion of Western Bean Cutworm, Striacosta albicosta (Noctuidae), into Michigan and Ohio

Abstract

The western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae) is native to the western United States, where it was first described as a pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.) (3). On corn, fourth and fifth instar larvae feed in the ear, reducing yield and grain quality. Since 2000, the western bean cutworm has spread eastward through Iowa, Minnesota, Illinois, and Missouri (1,2,4), into Indiana in 2005, and Wisconsin in 2006 (6). Before 2006, there were no records of western bean cutworm in the Michigan State University A. J. Cook Arthropod Collection or in collections at The Ohio State University, nor reports of larval injury to corn in Michigan or Ohio. In the summer of 2006, five and ten pheromone traps were set up in Michigan and Ohio, respectively (Fig. 1). Each trap was constructed from a one-gallon plastic milk jug cut to leave open side panels (5), and baited with a Scentry western bean cutworm pheromone lure (Great Lakes IPM, Vestaburg, MI) hung under the cap (Fig. 2). Traps were filled with a 50:50 mixture of water and commercial antifreeze and hung 1.5 m above the ground near corn. Traps were checked once per week from 1 July through late August; lures were changed once in late July. In Ohio, a total of three adults were captured, one in each of three counties during the first week of July (Fig. 1A). In Michigan, adults were captured later in the season, one each during the weeks of 8 to 14 and 15 to 21 July in Van Buren Co. and on the night of 24 July in Kalamazoo Co. (Fig. 1A). These were the first western bean cutworm adults recorded from either state.