The European corn borer, Ostrinia nubilalis (Hübner), is a damaging pest of numerous crops including corn, potato, and cotton. An understanding of the interaction between O. nubilalis and its spatial environment may aid in developing pest management strategy. Over a 2-yr period, approximately 8,000 pheromone trap catches of O. nubilalis were recorded on pivot-irrigated corn in northeastern Colorado. The highest weekly moth capture per pivot-irrigated field occurred on the week of 15 July 1997 at 1,803 moths captured. The lowest peak moth capture per pivot-irrigated field was recorded on the week of 4 June 1998 at 220 moths captured. Average trap catch per field ranged from approximately 1.6 moths captured per trap per week in 1997 to approximately 0.3 moths captured per trap per week in 1998. Using pheromone trap moth capture data, we developed a quantified understanding of the spatial distribution of adult male moths. Our findings suggest strong correlations between moth density and adjacent corn crops, prevailing wind direction, and an edge effect. In addition, directional component effects suggest that more moths were attracted to the southwestern portion of the crop, which has the greatest insolation potential. In addition to the tested predictor variables, we found a strong spatial autocorrelation signal indicating positive aggregations of these moths and that males from both inside and outside of the field are being attracted to within-field pheromone traps, which has implications for refuge strategy management.

Strategies for controlling pests are an integral part of any agricultural management plan. Most field crops, such as wheat (Triticum spp.) and corn (Zea mays L.) are managed as if they are homogeneous units. However, pests within fields are rarely homogenous. Development of plans that use targeted pest control tactics requires knowledge of the ecological drivers of the pest species. That is, by understanding the spatio-temporal factors influencing pest populations, we can develop management strategy to prevent or reduce pest damage. This study was conducted to quantify variables influencing the spatial variability of adult male western bean cutworm, Striacosta albicosta (Smith). Striacosta albicosta moths were collected in pheromone traps in two center pivot, irrigated corn fields near Wiggins, CO. We hypothesized that moth abundance would be influenced by the distance from the edge of the field, distance to nearest alternative corn crop and affected by anisotropic effects, such as prevailing wind direction. Greater trap catches of S. albicosta in each of the fields were found with increased proximity to the edge of the field, if the nearest neighboring crop was corn. Prevailing wind direction and directional effects were found to influence abundance. Results serve as a first step toward building a precision pest management system for controlling S. albicosta.