Forage alfalfa (Medicago sativa L.) is an important agricultural component of the western United States. However, the primary insect pest of alfalfa, alfalfa weevil, Hypera postica Gyllenhal (Coleoptera: Curculionidae), has developed resistance to lambda-cyhalothrin. In 2021 and 2022, a total of 14 alfalfa weevil samples were collected from Arizona, California, Montana, Oregon and Washington, were assayed for susceptibility to both type I and type II pyrethroid active ingredients, using a laboratory assay. Our findings indicate likely cross-resistance amongst type II pyrethroids and variable and/or limited cross-resistance to permethrin (type I pyrethroid) and no cross-resistance to bifenthrin (type I pyrethroid). In 2022, insecticide field trials were conducted in Arizona, Montana, and Washington, corroborating our laboratory findings from samples collected from the same locations. Indicating, that alfalfa weevil populations in the western United States that are resistant to lambda-cyhalothrin will also be resistant to other type II pyrethroid active ingredients. However, bifenthrin (type I pyrethroid) was the most efficacious pyrethroid active ingredient tested that controlled lambda-cyhalothrin resistant location samples in both our laboratory bioassays and field trials. Indicating limited or no cross-resistance between pyrethroid types.