Submitted to: Silverleaf Whitefly: 1997 Supplement to the Five Year National Research and
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 1997
Publication Date: N/A
Technical Abstract: We conducted studies to define B. argentifolii population development on long- and short-staple cotton cultivars and determine the influence of plant density and insecticides on whitefly populations, sticky cotton and cotton yields. We compared cotton lint stickiness for different methods of seed cotton sampling. Cotton plant densities of 10 or 40 K plants/acre had no effect on numbers of silverleaf whitefly adults, eggs, nymphs, extracte sugars from lint samples or thermodetector (TD) sticky cotton counts. Higher numbers of whiteflies occurred in early-season in Pima S-7 cotton than in DPL50 or DPL5415 cotton. Seasonal averages for sugars, percentages of total reducing sugars and TD counts were higher for DPL50 compared with Pima S-7 but not DPL5415. The first open cotton bolls subject to honeydew contamination occurred between 17 & 22 August. Most of the sugar analyzed from lint samples occurred during a 24 d period from 22 August to 15 September for all cultivars harvested 25 September. DPL50 and DPL5415 had 99 and 91% of the bolls open during 22 August to 25 September as compared to 76% for Pima S-7 resulting in lower sticky cotton counts for Pima S-7 compared with DPL50 but not DPL5415. Insecticide treatments reduced TD counts. Sticky cotton results for 20 boll randomly picked samples were comparable with results from total open cotton/plant harvests but both sample methods had lower individual sugar, percentage of total reducing sugars and TD counts compared with machine total cotton plot harvests.