Spinning experiments were conducted to study the impacts on fiber processing of alternative types of honeydew contamination and confirm the hypothesis that trehalulose (mostly present in whitefly honeydew) is the main source of concern when attempting to spin sticky cottons. Spinning tests using Suessen Fiomax 1000 and Suessen EliTe frames showed that both types of honeydew are, at least partially, cleanable and that the whitefly honeydew droplets are broken into smaller particles during the opening, blending, carding, and drawing operations. Regarding yarn quality, except for the yarn nep count, aphid honeydew contamination did not translate into negative effects on both yarn quality and productivity up to 26 high speed stickiness detector (H2SD) spots. For whitefly-contaminated cotton even 12 H2SD spots had a drastic negative impact, producing unacceptable yarn quality and productivity. Therefore, the threshold for acceptable performance in the mill for whitefly-contaminated cotton should be set well below 12 H2SD sticky spots.