Browsing by Author "Maia, Miguel"
Now showing 1 - 8 of 8
Results Per Page
Sort Options
- Beekeeping in Portugal. An updated overview focused on coping with varroaPublication . Maia, Miguel; Pereira, Óscar; Pires, Sancia; Murilhas, AntónioIn Portugal, there are no official, statistically validated, records that can allow an oblective data-based analysis of the national beekeeping sector. This was the first study that set out to try a first nationwide characterization of beekeepers and beekeeping operations most frequently carried out in the context of our apiculture, particularly the type of operations expected to impose some selection pressure on national populations of varroa.
- Current effectiveness of amitraz against Varroa in PortugalPublication . Pires, Sancia; Murilhas, António; Pereira, Óscar; Maia, MiguelThe 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.
- Eficácia actual do apistan e do apivar na luta contra a varroose em Portugal: relatório final.Publication . Pires, Sancia; Murilhas, António; Pereira, Óscar; Maia, MiguelA primeira fase deste projecto foi dedicada ao tratamento de dados baseado em 1003 questionários telefónicos, na tentativa de obter informações que nos permitiram caracterizar, de uma forma genérica, a apicultura nacional. Através dos resultados obtidos foi fornecida informação acerca da idade, escolaridade e formação do apicultor, assim como, acerca de alguns aspectos relacionados com o maneio apícola, entre os quais, o modo de utilização dos acaricidas (os acaricidas utilizados, a quantidade utilizada, a frequência e o local de aplicação dos tratamentos, a combinação de tratamentos), a substituição de ceras do ninho, a transumância, entre outros. Deste modo, foi possível identificar maiores probabilidades esperadas de possíveis fenómenos de populações de varroas resistentes ao fluvalinato e/ou amitraz e, permitiu-nos também contribuir para a caracterização da apicultura nacional.
- Eficácia actual do apistasn e do apivar na luta contra a varroose em PortugalPublication . Murilhas, António; Pereira, Óscar; Maia, Miguel; Pires, SanciaA Varroose é, praticamente a nível mundial, a principal patologia apícola associada às colónias de abelhas. Na Europa têm vindo a ser observados fenómenos, cientificamente comprovados, de crescente resistência da Varroa a vários acaricidas sintéticos, incluindo os que têm vindo a ser utilizados em Portugal. Nesta perspectiva o presente projecto visa, esclarecer qual o actual nível real de eficácia 'terapêutica' dos acaricidas que têm vindo a ser disponibilizados pelos serviços oficiais (Apistan I Apivar), no contexto específico da nossa apicultura. Fundamenta-se esta necessidade com a 'impossibilidade' de extrapolar, para a realidade nacional, os resultados obtidos nos vários estudos efectuados no estrangeiro, bem como face às medíocres condições em que, regra geral, tem vindo a ser efectuada a luta contra a varroose e também às repetidas denúncias apresentadas por muitos apicultores sobre a aparente observação de fenómenos de acentuada quebra de eficácia dos tratamentos anti-Varroa efectuados com Apistan I Apivar.
- Field and laboratory screening for fluvalinate-tolerant varroa populations in PortugalPublication . Pires, Sancia; Maia, Miguel; Murilhas, António; Pereira, ÓscarFollowing widespread claims of decreasing Apistan field efficacy, a large screening project was put into practice towards trying to identify Portuguese Varroa populations highly tolerant to fluvalinate. Approximately 12 thousand field-tests were carried out, for the most part based upon the “British National Bee Unit” field-testing methodology (with an extra blank control test added). From all studied colonies, 1536 allowed for conclusive field-testing (i.e. 3 or more Varroa were submitted to fluvalinate in a given test and no abnormal Varroa mortality was found in the respective control test). Using a 60 % fluvalinate-induced Varroa mortality border line, 878 of those colonies were considered to host fluvalinate-tolerant Varroa populations. On average, 18 mites were studied per colony that tested positive for fluvalinate-tolerant Varroa populations. The overall fluvalinate therapeutic efficacy, as regards Varroa populations hosted in those colonies, was only 26.4 +- 0.6 % (mean +- s.e.m.). Capped brood samples from honey bee colonies that had field-tested positive for fluvalinate-tolerant Varroa populations were later collected to provide Varroa for laboratory reassessment of fluvalinate-tolerance (basically, following Milani’s methodology). Even though we had to discard results obtained from approximately half of the collected brood samples (adding to a total of 172 samples, as a result of the insufficient numbers of mature Varroa they hosted), in many instances field-test outcomes could be later confirmed by laboratory tests.
- Fluvalinate-tolerant varroa populations rapidly loose their lead against apistanPublication . Pires, Sancia; Murilhas, António; Maia, Miguel; Pereira, ÓscarSince the early nineties, many Portuguese beekeepers have intensively used various ways of applying fluvalinate into their honey bee colonies. This behavior has imposed a strong selection pressure towards fluvalinate-tolerant Varroa populations, some of which were recently identified in a nationwide study (via fie ld and laboratory testing). Being able to locate such populations opened up the possibility to challenge them against rightly applied Apistan field treatments, as well as to estimate how promptly those populations move back to normal levels of susceptibility to this acaricide.
- How challenging to apivar field treatments are amitraz-tolerant varroa populations?Publication . Pires, Sancia; Maia, Miguel; Pereira, ÓscarPortuguese beekeepers depending on blind and repeated use of amitraz in fighting Varroa have meant a selection pressure towards amitraz-tolerant Varroa populations. Some of these Varroa populations were recently pin pointed during a nationwide monitoring effort (by field and laboratory testing), allowing for investigating the practical meaning such increased levels of tolerance have to properly applied Apivar field treatments and how quickly those populations regress to normal levels of susceptibility to amitraz.
- How resistant to fluvalinate are varroa populations in Portugal?Publication . Pires, Sancia; Murilhas, António; Maia, Miguel; Pereira, ÓscarThe varroa mite (Varroa destructor) was first detected in Portugal in 1986. Since then, there has been a widespread use of fluvalinate (Apistan, Klartan) in the attempt to cope with it. Following (i) various credible international reports of increased varroa resistance to fluvalinate and (ii) repeated claims from national beekeepers of poor efficacy of Apistan treatments, a large screening project was setup (2003/2004) for trying to identify honeybee colonies hosting varroa populations resistant to fluvalinate in continental Portugal.