ABSTRACT

Cotton producers increasingly are under pressure to reduce chemical use, control stickiness, avoid weather damage and make a profit in the face of the lowest cotton prices in history. Organic producers are called upon to produce a high quality fiber without using any chemicals at all. The thermal defoliation research reported here is an attempt to provide producers with additional tools to meet these objectives. Thermal defoliation gives organic producers a way to terminate their crop. Other producers may appreciate being able to eliminate insects that cause stickiness, to defoliate during bad weather and to harvest shortly after treatment. Thermal defoliation was shown to work in three states (and over three years in New Mexico) in Pima, Acala and upland cotton varieties. While defoliation (leaf drop) is not as great as that attained with chemical treatment, desiccation (leaf withering) is usually more pronounced, and almost instantaneous. Two weeks after heat treating at 300 F for 8 seconds (burning 13 gallons of propane per acre) plants were 60% defoliated and 80% desiccated.