First detection of resistance to deltamethrin in Spanish populations of the Mediterranean fruit fly, Ceratitis capitata

Abstract The control of the Mediterranean fruit fly (Medfly), Ceratitis capitata , in citrus orchards Spain is mainly based three insecticides (spinosad, lambda-cyhalothrin and deltamethrin) liberation sterile males. However, Medfly compromised by development resistance detection spinosad-resistant alleles field populations. We report here, for first time, to deltamethrin populations collected fields under different management strategies, including MagnetMed™ traps coated with this insecticide and/or spinosad used as bait sprays, even obtained from non-treated fields. Two deltamethrin-resistant strains (BP-delta Rfg-delta) were generated descendants some that showed lower susceptibility deltamethrin. Both low traps, moderate Ceratipack lacked cross-resistance lambda cyhalothrin. Our data suggest was mediated P450 enzymes, since bioassays synergists PBO reverted a population laboratory strains, whereas effect DEF DEM minor no mutations found VGSC gene. inheritance both completely recessive, autosomic did not fit mortality expected recessive character monogenic or digenic model. also presented fitness cost terms males’ weight, females’ longevity lifetime fecundity, more pronounced BP-strain than Rfg-delta strain. results highlight need implement strategies prevent failures.