text: This study guide is for agricultural pest control advisers and others interested in information regarding harvest aid use in California cotton. Harvest aid chemicals are applied to cotton to increase the rate of leaf loss and desiccation, which allow timely harvesting operations. Using this guide, you can make better decisions on what harvest aid chemical to use, economic considerations, the timing of application, what chemicals to apply, and at what rate. You will also learn how to include other harvest factors into your decisions, including weather, crop maturity, and environmental conditions. This publication #4043 is available in the Madera County University of California Cooperative Extension Office for $5.00.