RELATIONSHIP OF BEE VIRUS AND VARROA LOADS IN THE SURVIVAL OVER THE WINTER OF HONEY BEE IN ARGENTINA.

REYNALDI F. J.; SGUAZZA G.H,; ALTAMIRANO R.; PECORARO M.I.R.; GALOSI, C.M.

Kiev

Congreso; 43th International Apicultural Congress. APIMONDIA; 2013

International Bee Research Association

Argentinian beekeepers have reported increased mortality in overwintering honeybee, Apis mellifera L. colonies, since 2007. Viral infections are often cited as one of the potential cause for increased mortality. In addition, the global spread of Varroa destructor probably has resulted in a significant change in the prevalence, distribution and virulence of viruses. In this study, we report the first survey of six RNA bee viruses on honeybee and varroa, and their effect on overwintering survival in Argentina honey bee colonies. Thirty three honey bee colonies, with undetectable levels of Varroa destructor were selected in the summer of 2010 and left untreated until the following summer in 2011. After honey harvest in February 2011, we sampled adult bees and varroa from all the colonies of the assay. Adult bee and varroa samples were analyzed by using RT-mPCR for identification of following virus: Acute bee paralysis (ABPV), Chronic bee paralysis (CBPV), Israeli acute paralysis (IAPV), Black queen cell (BQCV), Sacbrood (SBV) and Deformed wing (DWV). Varroa mite prevalence in these samples was quantified. We also sampled three more times in autum and spring of 2011 and summer 2012. No colony mortality was record during the two years trail. DWV and ABPV were the most prevalent of the detected honey bee viruses. Co-infection with more than two viruses was seen in summer and spring but had not an appreciable negative effect on colony survivorship. The control of mites had a clearly effect on the control of varroa loads and reduced the presence of certain viruses (specially DWV) in the colonies. However, other viruses studied,such as ABPV and BQCV, are dispersed independently of the presence of mites. Other factors not well determined might influence the dynamics of viral infection on the colonies. These studies have not linked the presence of virus with colony mortality.