Author
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Naranjo, Steven |
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Henneberry, Thomas |
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Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Proceedings Publication Acceptance Date: 4/1/2002 Publication Date: 6/1/2002 Citation: N/A Interpretive Summary: Technical Abstract: Sticky cotton continues to be a worldwide problem that may presently be considered by the cotton industry as the most serious factor affecting cotton quality. Plant-produced sugars have been implicated in the sticky cotton problem; however, a high percentage of the documented lint stickiness problems have been associated with the occurrence of honeydew-producing insects such as aphids and whiteflies. Honeydew induced stickiness is problematic at many post-harvest phases of lint processing including ginning, carding, and particularly spinning. The sticky cotton problem in the U.S. has increased with recent population outbreaks of the whitefly Bemisia tabaci and research is currently addressing an array of issues from characterization of sugars to management of plant and insect sources. The accurate determination of cotton lint stickiness in the field could greatly aid management and research efforts. Field sampling of stickiness could augment pest monitoring techniques and improve overall decision-making for pest suppression and also identify unacceptable levels of stickiness at harvest that may require some remedial action such as the use of enzyme treatment systems that are currently being investigated. Our research targets the development of standard methodologies for collecting lint samples from fields to ensure statistically precise estimates of stickiness. Two assay systems were investigated, the manual thermodetector (SCT) and the high speed (automated) sticky cotton thermodetector (H2SD). The development of sampling plans involves four inter-related components. The newest H2SD system consistently detects more thermodetector spots than the SCT and the relationship between the platforms appears to be nonlinear, at least for field-collected samples encompassing a very wide range of stickiness levels. The distribution of sticky lint in the field is random regardless of which platform is used to assay the lint. Time and cost considerations are critical to any sampling procedure. This analysis takes into account the relative costs of sample collection in the field and the time required to complete a single assay with each platform. The assay system used is critical to the development of a final field sampling plan; however, there is considerable flux in the industry relative to a standard platform for stickiness testing. Given this uncertainty, we have developed sampling plans for both platforms. Overall sampling costs are much lower for the H2SD because of the speed with which samples can be assayed. Sampling efficiency could be further improved with sequential sampling strategies or with sample plans focused on categorizing rather than estimating actual levels of stickiness. These sampling applications await further research to define critical levels of stickiness and/or the implementation of wide-scale testing where any time savings would be at a premium. |
