ENZYME TREATMENT OF HONEYDEW–CONTAMINATED COTTON FIBER

Cotton fiber contaminated with insect honeydew causes serious processing problems in cotton gins and textile mills. The use of a carbohydrate–degrading enzyme to reduce the stickiness of honeydew–contaminated cotton was tested in a system designed to simulate cotton modules. Miniature cotton modules consisting of 1.8–m 3 plastic–lined wooden boxes were packed with seed cotton contaminated with sweetpotato whitefly, Bemisia tabaci (Gennadius), honeydew. Treatments were a factorial arrangement of 0–, 295–, and 824–enzyme units/kg seed cotton at 8, 10 and 12% seed cotton moisture. As the seed cotton was packed into the boxes each kg was sprayed with carbohydrate–degrading enzyme in water at rates of between 0.08– and 0.26–L/kg seed cotton. The cotton in these boxes was compressed to a density of 146 to 216 kg/m 3 . The thermal behavior and stickiness of the seed cotton in the simulated modules, and the length, strength, and color of the cotton fiber were measured during a six–week storage period. Sprays containing medium or high enzyme rates and 8% lint moisture content did reduce the stickiness and extractable sugar content of the fiber but at higher rates of enzyme application moduled cotton became discolored after extended module storage.