Challenges in varroosis control: preliminary investigation of amitraz resistance in varroa destructor in Portugal

• Autor(a) principal: Costa, Maíra
• Data de Publicação: 2024
• Outros Autores: Lopes, Ana, Yadró Garcia, Carlos A., Gonçalves, Mariana Lousada, Coelho, Liliana, Pires, Sancia, Pinto, M. Alice, Henriques, Dora
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/30329
• topic: Varroa destructor; Amitraz; Octβ2R; Portugal; Research Subject Categories::TECHNOLOGY::Chemical engineering::Food technology

Varroosis is a disease caused by the ectoparasitic mite Varroa destructor, identified as one of the most significant global threats to the honey bee (Apis mellifera). The most effective control of this mite is through synthetic or organic acaricides. However, the excessive and repeated use of synthetic acaricides has led to the development of resistance. Amitraz is a synthetic pesticide commonly used in the control of V. destructor, but resistance to this compound has been observed. Previous studies observed a substitution of asparagine by serine at position 87 (N87S) of the Octβ2R gene, associated with amitraz resistance in France, and a substitution of tyrosine by histidine at position 215 (Y215H), associated with amitraz resistance in the USA. Building upon this knowledge, we aim to implement the first screening in Portugal for mutations associated with V. destructor resistance to amitraz. Unlike several European countries and the USA, Portugal lacks information regarding gene variation implicated in V. destructor resistance to amitraz, as well as allelic frequencies and their geographical distribution. To investigate the resistance mechanism, primers were developed to amplify the two known target regions of amitraz in V. destructor. DNA was extracted from individual female varroa mites using a commercial extraction kit, and the obtained DNA was PCR-amplified with the developed primers, followed by Sanger sequencing. With the knowledge obtained, we hope to assist beekeepers in selecting the most suitable acaricide to manage V. destructor in their apiaries and gain a deeper understanding of amitraz resistance in Portugal.