Bemisia argentifolii (Homoptera: Aleyrodidae) Population Relationships to Cotton and Lint Stickiness in Long and Short Staple Cottons

Whitefly honeydew contamination resulting in sticky cotton lint is a significant problem in the textile industry throughout the world. We conducted studies in 1995 and 1996 to determine the effects of cotton cultivars, cotton plant densities, and insecticides on Bemisia argentifolii Bellows & Perring populations and the subsequent effects on honeydew cotton lint contamination. In 1995, cotton plant densities of 25 or 100,000 plants per hectare had no effect on numbers of B. argentifolii, adults, eggs, or nymphs based on adult leaf turns and immatures counted on leaf disks. There also was no effect on extracted honeydew sugars from lint samples or thermodetector sticky cotton counts (the international standard for measuring cotton lint stickiness). Higher numbers of whiteflies occurred in early-season in 'Pima S-7' cotton than in 'Deltapine (DPL) 50' in 1995 and 1996 or 'DPL 5415' cotton in 1995. In 1995, amounts of trehalulose and melezitose (insect honeydew sugars) extracted from cotton lint and thermodetector counts of lint samples were higher for DPL 50 compared with Pima S-7 but not DPL 5415. Insecticide treatments, in both years, reduced thermodetector counts and honeydew sugars extracted from lint. Increases in thermodetector sticky cotton counts and trehalulose and melezitose were significantly correlated to increasing B, argentifolii nymphal and adult populations. Thermodetector sticky cotton counts did not reach levels of concern (≥5) until adult leaf-turn counts were 8.9 or when all life stage nymphs were 3.2 per square centimeter of leaf disk during the open mature cotton boll period.