Abstract Populations of the cotton leafperforator, Bucculatrix thurberiella Busck, increased throughout the growing season on ‘Pima S‐5’ (Gossypium barbadense L.) and ‘Deltapine 16’ (G. hirsutum L.) cottons grown under 7‐, 14‐, and 21‐day irrigation schedules. Cotton leafperforators did not prefer one cotton cultivar over the other, but significantly larger numbers were found on plants in the 21‐day irrigation schedule plots as compared to the other treatments. Although large numbers of the insect were collected from all plots late in the season, early season populations were not high enough to reduce yields of cotton lint. Likewise, irrigation schedules did not appear to influence cotton production although yield of Pima S‐5 on the 7‐day (wet) irrigation was slightly lower than in the other treatments. Cotton leafperforators did not prefer one cotton cultivar over the other, but significantly larger numbers were found on plants in the 21‐day irrigation schedule plots as compared to the other treatments. ...