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Current effectiveness of amitraz against Varroa in Portugal


The varroa mite (Varroa destructor) was first detected in Portugal in 1986. Since then, there has been a frequent use of amitraz (Apivar, Acadrex) in the attempt to cope with it. Following (i) various credible international reports of increased varroa resistance to amitraz and (ii) regular claims, by national beekeepers, of poor efficacy of Apivar treatments, a large screening project was setup (2003/2004) for trying to identify honey bee colonies hosting varroa populations resistant to amitraz in continental Portugal. As a first step, approximately 1200 beekeepers were enquired nationwide, with a view to building up a rank of apiary-specific probability indexes of varroa resistance to fluvalinate. From those beekeepers, approximately 4.000 colonies were field-tested in a similar way to the “British National Bee Unit” field testing methodology for fluvalinate, and compared to blank control tests (same kits and methodology, but without using amitraz). From those investigated colonies, 1579 allowed conclusive testing (i.e. where 3 or more varroa per honey bee colony were submitted to the action of amitraz). Approximately 17 % (272) of these colonies were considered to host varroa populations resistant to amitraz (using, as border line, 80 % of amitraz induced varroa mortality). Furthermore, the efficacy of amitraz in the field tests carried out on those 272 colonies only reached an average of 60.1 % (s.e.m. = 1.2 %)

Palavras Chave

Amitraz; Varroa; Abelhas; Portugal / Amitraz; Varroa; Honey Bees; Portugal.

Tipo de Apresentação
Comunicação oral
Tipo de Revisão
Âmbito Geográfico
Área de Trabalho

Pires, S.; Murilhas, A.; Pereira, O.; Maia, M. (2005). Current effectiveness of amitraz against Varroa in Portugal. 39th Apimondia International Apicultural Congress, pp. 78. Apimondia. Dublin, Irlanda.