Topical application bioassays of bifenthrin and λ-cyhalothrin were conducted on field-collected populations of Listronotus maculicollis Kirby (Coleoptera: Curculionidae) from eight southern New England golf courses, six in Connecticut, one in Massachusetts, and one in Rhode Island. Concentrations versus mortality regression lines were estimated to compare the LD₅₀ values and resistance ratios for each insecticide and each population. The LD₅₀ ranges for bifenthrin and λ-cyhalothrin were 1.80–244.67 ng per insect and 0.52–159.53 ng per insect, respectively. The field-collected strains showed low to high levels of resistance to bifenthrin (6.1–135.9-fold) and λ-cyhalothrin (28.7–306.8-fold). This is the first report of insecticide resistance in this species. The loss of pyrethroid efficacy is making control of Listronotus maculicollis more challenging.