Harvest aid materials provide a valuable tool for cotton management in short season environments. By removing leaves and opening mature bolls, timing of cotton harvest can be improved, while sources of leaf trash are removed from the plant. A series of field trials compared common, effective harvest aids in Missouri from the 1991 to 1993. In the short growing season of 1992, yields were increased by the combination of Folex + Prep. The same treatment resulted in reduced micronaire in 1991 and 1992. In 1993, yields were lower and a cool defoliation period produced no differences in defoliation, micronaire, or yield.