|Mcalister Iii, David|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/8/2003
Publication Date: 8/1/2003
Citation: Funk, P.A., Armijo, C.B., McAlister, D.D., Brashears, A.D., Bancroft, J.S., Roberts, B.A., Lewis, B.E. 2003. Thermal defoliation. National Cotton Council. CD-ROM p. 2549-2553. Interpretive Summary: Using hot air as a defoliant provides organic producers with an important tool. Other producers may also appreciate this alternative to chemical defoliation. Three years of research (and one season in three states) are summarized, demonstrating the effectiveness of this method. Unexpected benefits include the ability to defoliate during bad weather, to harvest two days later independent of intervening temperatures, and to stop insects responsible for stickiness.
Technical 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.