Chemigation efficacy of bifenthrin and chlorantraniliprole for Striacosta albicosta (Lepidoptera: Noctuidae) management in corn under different irrigation depths

Western bean cutworm, Striacosta albicosta Smith (Lepidoptera: Noctuidae), is a significant pest in Midwestern U.S. corn ( Zea mays L.) production. In Nebraska, foliar application of insecticides at the tasseling stage of corn is commonly performed via chemigation using overhead irrigation systems (center pivots). However, the efficacy of various chemigation practices for S. albicosta have not been well explored. A two-year field study was conducted to evaluate the efficacy of chlorantraniliprole and bifenthrin, applied at both minimum and maximum label rates for bifenthrin (36.8 and 112.1 g a.i. ha −1 ) and chlorantraniliprole (52.7 and 75.1 g a.i. ha −1 ), using two application depths (6.35 mm and 19.05 mm). In 2021, chlorantraniliprole reduced ear feeding injury compared to bifenthrin 28 days after application (DAA). In 2022, no differences were observed between the two insecticides for the ear feeding injury. Throughout both field seasons, no S. albicosta larvae were found in plots treated with chlorantraniliprole during ear assessments at 28 DAA. This was not the case with bifenthrin, which provided moderate control. Application depths of the applied insecticides did not influence ear feeding injury. Our results indicate that insecticide selection for S. albicosta management is more important than the depth of the application. Chlorantraniliprole provided superior larval control, supporting its use in chemigation-based management strategies for S. albicosta in corn. • Active ingredient is more critical than application depth for Striacosta albicosta chemigation. • Chlorantraniliprole had fewer larvae and lower ear feeding injury than bifenthrin. • Lower application depth (6.35 mm) enhances chemigation efficiency than higher application depth (19.05 mm) without affecting efficacy.