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This study aimed to detect mutations associated with pyrethroid resistance mechanism in different populations of Varroa destructor from Uruguay and Argentina with different degree of susceptibility to this family of acaricides. Bioassays were performed to evaluate the degree of susceptibility to flumethrin and tau-fuvalinate; then mites were studied in order to determine the presence or absence of the resistance-associated mutations by sequencing a region of the sodium channel gene. In the mites studied from Colonia, which showed resistance to flumethrin and susceptibility to tau-fluvalinate in the bioassays, L925V mutation was observed in heterozygous and homozygous state. The presence of the wild-type allele in homozygous state was identified in all mites from Treinta y Tres, in which acaricides have never been used. The mite population from Mar del Plata through bioassays were determined as susceptible to both pyrethroids, however, genotyping results showed the presence of heterozygous individuals (925 V/L) as well as homozygous wild type (925L), while homozygous resistant individuals (925V) were present at low frequency. This would suggest that this population presents a great potential to give a generalized resistance to pyrethroids. This study represents the first report of a L925V mutation in resistant mites to flumethrin from South America. [ABSTRACT FROM AUTHOR]

Lotmaria passim (Kinetoplastea) is considered the most prevalent as well as the most virulent trypanosomatid associated to the European honey bee Apis mellifera. We used qPCR to screen for the presence of this parasite in 57 samples from ten Argentinian provinces, and were able to detect its presence throughout most of the country with 41% of the samples testing positive. In a retrospective analysis, we detected L. passim in 73% of honey bee samples from 2006 showing that this flagellate has been widely present in Argentina for at least ~15 years. Additionally, three primer sets for L. passim detection were compared, with the pair that produced smallest PCR product having the best detection capability. Finally, we also found L. passim DNA in 100% (n = 6) of samples of the mite Varroa destructor. The role of this ectoparasite in the lifecycle of Lotmaria , if any, remains unrevealed. Unlabelled Image • The trypanosomatid Lotmaria passim is widely present in Argentina since 2006. • Forty-one percent of the analyzed honey bees were Lotmaria passim -positive. • All analyzed Varroa destructor individuals harbored DNA of Lotmaria passim. [ABSTRACT FROM AUTHOR]