Summaries of Arkansas Cotton Research 2003 261 Bt COTTON PERFORMANCE IN ARKANSAS IN 2003: AN ECONOMIC EVALUATION K. Bryant, J.K. Greene, G..M. Lorenz, B. Robertson, and G. Studebaker 1 RESEARCH PROBLEM The number of transgenic cotton cultivars available for commercial production has increased greatly in recent years. Cotton producers now have multiple choices when choosing transgenic cotton cultivars. The choice of cultivar now dictates the insect and weed control programs that will or can be used. It is estimated that, in 2003, at least 77% of Arkansas’ cotton acreage was planted to a stacked-gene cultivar while an additional 11% was planted to a single-gene Roundup Ready cultivar (Anonymous, 2003). An economic evaluation of insect control methods provides valuable information to producers and researchers. BACKGROUND INFORMATION The University of Arkansas, in cooperation with Arkansas cotton producers, county agents and industry representatives, has implemented side-by- side comparisons of Bollgard cotton cultivars to non-Bt cultivars each year beginning in 1996 (Bryant et al., 2002). In 2003, stacked-gene cultivars were compared to Roundup Ready cultivars in some cases and to conventional cultivars in other cases. This article presents the economic results of those comparisons. RESEARCH DESCRIPTION Four cotton growers in southeast Arkansas and two in northeast Arkansas agreed to cooperate in these comparisons. In all areas, fields were chosen that were very similar in nature. Each field was managed using Best Management Practices for that field and cultivar. The primary differences in management between the two fields being compared in each observation involved insect control due to the presence or absence of the Bt gene. In cases where the stacked-gene cultivar was compared to a conventional cultivar, herbicide programs also differed. However, differences in herbicide applications were ignored in this analysis. To 1 Area extension specialist, extension entomologist, Southeast Research and Extension Center, Monticello; extension entomologist, cotton extension agronomist, Cooperative Extension Service, Little Rock; and entomologist, Northeast Research and Extension Center, Keiser, respectively.