Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 1996
Publication Date: N/A
Interpretive Summary: Honeydew is a sugary substance that is excreted by silverleaf whiteflies. When honeydew falls on lint of open bolls it creates sticky cotton that becomes a major problem in all subsequent cotton lint processing. Trehalulose is the most abundant sugar in honeydew produced by silverleaf whiteflies. We found that trehalulose amounts in cotton lint and simulated dcotton bolls increased with increasing exposure in whitefly infested cotto fields. Highest amounts of trehalulose were covered from lint from bolls near the bottom of the plant compared with lint from bolls at the top of the plant. Sticky cotton ratings were highly correlated with amounts of trehalulose in cotton lint. trehalulose was also highly correlated with numbers of whiteflies. Rainfall of 4.8 cm in a 48 hour period reduced sticky cotton ratings to non-sticky levels.
Technical Abstract: Trehalulose and melezitose produced by Bemisia argentifolii Bellows & Perring accumulated in cotton, Gossypium hirsutum L., lint in open cotton bolls on plants and on lint on harvested bolls in trays suspended in infested plants. Amounts accumulated were correlated positively to increasing numbers of exposure days. Fructose, glucose, and total reducing gsugars increased but results were variable, probably because these sugars, although found in Bemisia honeydew, also normally occur in cotton lint. Minicard sticky cotton ratings were correlated positively to increased amounts of all sugars tested. Rainfall (4.8 cm in a 48-h period) reduced amounts of all sugars and minicard sticky cotton ratings. Accumulated sugars and minicard sticky cotton ratings were reduced in insecticide-- treated compared with untreated fields. Trehalulose, melezitose, fructose, and glucose that accumulated on clear plastic-wrapped styrofoam balls were correlated positively to exposure time in B. argentifolii infested cotton fields. Amounts of all sugars, in general, were higher in clear plastic- wrapped balls placed at the middle and bottom of the plant as compared with the top of the plant. Amounts of trehalulose, melezitose, and fructose, but not glucose, were significantly higher on lint from bolls at plant nodes 9--14 as compared with nodes 15--20.