Assessing the Risk of Establishment by Pink Bollworm (Lepidoptera: Gelechiidae) in the Southeastern United States

Abstract

Pink bollworm, Pectinaphora gossypiella (Saunders), has failed to establish economically damaging populations on southeastern U.S. cotton (Gossypium spp.). Failure to establish may be the result of prevention and quarantine programs or the physiological tolerances of the species. The objectives of this study were to determine which regions within the southeastern United States might support pink bollworm survival and reproduction and which environmental factors might preclude establishment. Three independent analyses based on logistic regression of output from climate matching software, Climex, indicate that the probability of establishment was >50% in parts of Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Virginia, and Tennessee. At least 2 analyses concurred that the probability of establishment was ≥80% in portions of Arkansas, Louisiana, Mississippi, Alabama, Florida, and Georgia. All logistic regression models correctly classified 89-93% of the locations where pink bollworm occurs in the southwestern United States or does not occur outside the United States cotton belt. The models incorrectly classified 13-18% of the cases where successful establishment was predicted and 5-8% of cases where establishment was considered unlikely. Cold winter temperatures, causing direct mortality, or cool summer temperatures, providing inadequate degree-days for development, reduce the probability of establishment in more northern states. Slowed population growth caused by excessive moisture also lessens, but does not eliminate, the chances for establishment in certain southeastern states. These analyses do not indicate the potential severity of infestations. Nevertheless, the risk assessment suggests that monitoring efforts for presence and establishment of pink bollworm in the southeastern United States are warranted.