Susceptibility levels of Hungarian pollen beetle (Coleoptera: Nitidulidae) populations to lambda-cyhalothrin

Abstract

The pollen beetle (Brassicogethes aeneus Fabricius, 1775) is one of the most harmful pests of winter oilseed rape. Resistant populations have already appeared and spread in Europe due to the misuse of pyrethroid insecticides. Therefore, lambda-cyhalothrin resistance tests were performed on adult beetles collected in four Hungarian habitats according to the coated glass vial assay of the Insecticide Resistance Action Committee (IRAC) in 2018 and 2019. According to the results, all tested individuals were classified into the resistant category, as the mortality at the concentration of 0.075 μg/cm² of the active ingredient, which corresponds to the typical field rate, was only 52–55%. From the cumulated data of the two consecutive years and four sampling sites, the L.D. 50 (0.047 μg/cm²) and the L.D. 90 (0.148 μg/cm²) values of lambda-cyhalothrin were also determined. Total mortality was observed only for the 150% (0.113 μg/cm²) and 200% (0.15 μg/cm²) treatments. Preventing the further spread of pyrethroid-resistant pollen beetle populations and controlling them has become essential in Hungary; therefore, additional monitoring of pollen beetles is critical in developing strategies to address insecticide resistance.

Keywords

• brassicogethes aeneus
• pyrethroid resistance
• monitoring