Damaging populations of the cotton fleahopper, Pseudatomoscelis seriatus, colonized cotton in Northeast Arkansas in 2001. Although the insect has occasionally been observed during the past and is routinely listed as a pest of Arkansas cotton, it has not previously been a damaging pest of cotton in this region of Arkansas. Densities observed on cotton in 2001 were unusually high and persisted throughout the growing season. Multiple insecticide applications were required to protect the crop. Changing cultural practices that allow preferred host plants, especially cutleaf evening primrose (Oenothera laciniata), to remain within production fields at the seedling to squaring stage of crop development are suspected contributors to establishment of the cotton fleahopper on cotton. Others factors that may have contributed to this unusual pest problem were high population densities of the fleahopper, extreme dry weather that triggered early irrigation of cotton, and the abundance of many broadleaf weeds on field borders. This report chronicles observations made on cotton fleahopper abundance on wild and cultivated hosts throughout the 2001 crop-growing season. Implications to area-wide management and the tracking of insect population across whole farms or communities are also discussed in relation to the cotton fleahopper and its association with weed and crop hosts.