Use of Soil Sterilants to Defoliate and to Terminate Growth of Irrigated Cotton1

Abstract

AbstractThe conventional approach of applying harvest‐aid chemicals to leaves of luxuriantly growing cotton plants, Gossypium hirsutum L., often results in partial or top defoliation followed by secondary growth. This study was initiated to test a new concept of cotton defoliation. The application of 61 liters/ha of a 32.7% aqueous solution of sodium methyl dithiocarbamate in the irrigation water to luxuriantly growing cotton plants resulted in termination of plant growth and complete leaf defoliation. Defoliation was completed within 10 days from time of application with full size, immature bolls opening in about 20 days. There was no evidence of plant regrowth after 75 days. The cotton plants were ideally suited for mechanical harvest. Although the chemical is too expensive to be economically feasible, we suggest that luxuriantly growing cotton plants can best be defoliated by destroying the conductive tissues of the root and/or lower portion of the stem and that further testing of this concept be initiated.