Risk factors associated with the ocurrence of Nosemosis (Nosema sp.) in the south of Buenos Aires, Argentina

PACINI A; PARRA GONZÁLEZ G; GUAGLIARDO SE; MOLINER A; PALACIO M; CRISANTI, P; SCHMID E ; BULACIO CAGNOLO N; BEDASCARASBURE E; RODRIGUEZ G; PARRA GONZALEZ J; ANGELETTI B; GIACOBINO A; FIGINI E

Estambul

Congreso; 45th Apimondia International Apicultural Congress Istanbul Turkey September 29 th 4 th October; 2017

Beekeeping is an important economic activity in Villarino and Patagones, in the south of Buenos Aires Province. However, honey production was reduced in the last 20 years. Nosemosis disease is one of the major sanitary problems linked to colony losses and reduced honey production. The objective of our work was to identify the risk factors associated with the ocurrence of Nosemosis based on an epidemiological study Potential explanatory variables were obtained from a checklist questionnaire answered by the beekeepers (n=27) in order to gather information about commonly performed management practices and the environment where the colonies were placed. Within each apiary, a minimum of six colonies or 10% of the total colonies were randomly selected to evaluate Nosema spp. sporulation level (abundance of Nosema spp.) and V. destructor infestation level in autumn (O2015) and spring (P2015) of 2015 and autumn 2016 (02016) (n=207).A single variable analysis with apiary as random effect was conducted for selecting explanatory variables potentially associated with the log of Nosema spores/ bee. Variables with a p-value ≤ 0.20 were selected for a subsequent multivariable analysis. Multivariable logistic regression analyzes with apiary as random effect were performed using a generalized linear mixed model (GLMM) to evaluate the effect of the selected explanatory variables. In the single variable analysis in O2015 and O2016 the frequency of queen replacement in the apiary and old combs replacement per colony per year (P=0,18 and P=0,13) selected, but in the final model, this variables were not significantly associated with the occurrence of Nosemosis. In P2015 and 02016, the infestation with Varroa (P=0,028, P=0,011) was associated with the occurrence of Nosemosis. An efficient control of Varroosis in autumn, and practices like queen replacement every two years and three comb replacement per colony per year, could be considered as protection factors for the occurrence of Nosemosis.