Pyrethroid resistance in populations of Listronotus maculicollis (Coleoptera: Curculionidae) from southern New England golf courses.

Topical application bioassays of bifenthrin and lambda-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 lambda-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 lambda-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.