The Utilization of Diplodia-Damaged Boll-Rot Cotton

Abstract

A limited quantity of specially selected seed cotton that had been damaged severely in the field by the common boll-rot fungus Diplodia sp. was roller-ginned and processed, along with a white control cotton, into blends containing 2.5%, 5.0%, 10.0%, and 35.0%. by weight, of the Diplodia-damaged lint. It was shown that the 35.0% blend could not be spun into a 38/1 (16 tex) yarn without an excessive number of ends down. The 10.0% blend could be utilized more efficiently in coarser-than-38/1 (16 tex) yarns. The 2.5% and 5.0% blends were spun into 38/1 (16 tex) yarns without an excessive number of ends down. The yarns from these two blends did not differ significantly from yarns spun from the control cotton in length uniformity, appearance grade, or yarn breaking tenacity and elongation. All cases of reduced processing efficiency and product quality in any of the blends, in comparison to the white control, were shown to be related to the short fiber content of the blends. Diplodia-damaged and undamaged bolls occur regularly together within a single cotton field, with a resulting admixture of the two kinds of fiber in the bale. Field observations suggest that in commercial bales amounts of fungus-damaged fiber in excess of that represented by the experimental 5% blend here employed are rare.