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Identification and risk assessment of spinosad resistance in a California population of Drosophila suzukii
Author(s) -
Gress Brian E,
Zalom Frank G
Publication year - 2019
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.5240
Subject(s) - spinosad , drosophila suzukii , biology , pest analysis , population , toxicology , drosophila (subgenus) , integrated pest management , infestation , biopesticide , microbiology and biotechnology , horticulture , drosophilidae , agronomy , drosophila melanogaster , pesticide , environmental health , medicine , genetics , gene
Background The bioinsecticide spinosad is among the most widely used insecticides for managing spotted‐wing drosophila, Drosophila suzukii (Matsumura), and is critical for preventing fruit infestation in organic berry production. Recent reports, however, have raised concerns that the efficacy of this material is declining in fields near Watsonville, CA, a major hub of commercial berry production in the USA and the first location where D. suzukii was reported in North America. Results In this study, we performed dose–response analyses on D. suzukii from commercial raspberry plantings near Watsonville as well as a second untreated site in California using a widely implemented bioassay protocol. We found that Watsonville flies exhibited spinosad LC 50 values 4.3–7.7 times higher than those from the untreated location and 11.6–22.4 times higher than previously reported susceptible baselines. Additionally, tolerance to spinosad continued to increase after additional selection for five generations, though this result was only statistically significant after prolonged exposure to residues. Conclusions These findings confirm that spinosad resistance is emerging in the Watsonville area and document the first known occurrence in the USA, presenting an urgent need for the development of alternative management strategies to control this pest. Additional work is needed to resolve the underlying molecular mechanism(s) that confers spinosad resistance in D. suzukii and assess the potential for this trait to spread into new populations. © 2018 Society of Chemical Industry