Supercooling Point of Western Bean Cutworm (Lepidoptera: Noctuidae) Collected in Eastern Nebraska

Abstract

Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctui-dae), is a pest of maize and dry beans that has recently undergone a northeastern range expansion in North America. In order to assess the cold tolerance of S. albicosta, we determined the supercooling point of lab and field collected late instar larvae and pre-pupae. Individuals were attached to fine contact ther-mocouples and cooled at 1°C per minute to detect heat released due to freezing of body fluids. Mean supercooling points decreased as larvae developed into later life stages. Pre-pupa collected in late fall had a mean supercooling point of -12.63°C. This research is the first documentation of cold tolerance measures for S. albicosta and will aid in designing future cold tolerance experiments and predicting S. albicosta population densities based on winter temperatures.