A pan-European epidemiological study reveals honey bee colony survival depends on beekeeper education and disease control

Reports of honey bee population decline has spurred many national efforts to understand the extent of the problem and to identify causative or associated factors. However, our collective understanding of the factors has been hampered by a lack of joined up trans-national effort. Moreover, the impacts of beekeeper knowledge and beekeeping management practices have often been overlooked, despite honey bees being a managed pollinator. Here, we established a standardised active monitoring network for 5 798 apiaries over two consecutive years to quantify honey bee colony mortality across 17 European countries. Our data demonstrate that overwinter losses ranged between 2% and 32%, and that high summer losses were likely to follow high winter losses. Multivariate Poisson regression models revealed that hobbyist beekeepers with small apiaries and little experience in beekeeping had double the winter mortality rate when compared to professional beekeepers. Furthermore, honey bees kept by professional beekeepers never showed signs of disease, unlike apiaries from hobbyist beekeepers that had symptoms of bacterial infection and heavy Varroa infestation. Our data highlight beekeeper background and apicultural practices as major drivers of honey bee colony losses. The benefits of conducting trans-national monitoring schemes and improving beekeeper training are discussed

Varroacidal Efficiency of Treatment with Amitraz in Honey Bee Colonies with Brood

Field trials were conducted to evaluate the effectiveness of amitraz fumigation against Varroa destructor in honey bee colonies with brood. Within this project the following aspects were taken into consideration: strength of colony, the number of treatments, time intervals between treatments and way of its performance. Honey bee colonies with brood were fumigated four times with one tablet of Apiwarol® per each treatment every four, six, eight and ten days. The tablets with amitraz were burned in the electrical device Wakont or directly in hives. In case of amitraz fumigation with Wakont even four treatments reduced infestations of V. destructor to a limited extent, on average from 40 to 61% of mite populations. A similar effectiveness among the treatments has been ascertained regardless of intervals between them. The efficacy of amitraz combustion in hives was slightly higher and statistically significant only after four treatments. Moreover, beyond brood area, the population of worker bees turned out to determine treatment efficacy with amitraz in this form and modes of administration. In honey bee colonies with brood, even four amitraz fumigations do not decrease the level V. destructor infestation to the extent that it is safe for wintered bees

The Spring Assessment of Nosema Spp. Infection in Honey Bee Colonies (Apis mellifera L.) - Sampling as an Important Aspect of a Reliable Diagnosis

The objective of the research was a comparative assessment of the infection levels of Nosema spp. in honey bees collected from different areas of the hive. A total of 588 honey bee colonies were sampled in spring (April-May) 2015 and 2016 through the simultaneous collection of dead worker bees from the bottom board of the hive and live bees from peripheral combs. A microscopic assay of composite samples of 60 bees was used for the detection and quantification of Nosema spp. spores. Consistent positive results of laboratory tests (detection of Nosema spp. spores in both live and dead bee samples) were achieved for 28% of colonies from surveyed group. In 36% of colonies both types of samples were Nosema-negative. Spores of Nosema spp. were detected solely in worker bees from the bottom board or exclusively in bees from nests in every 18% of sampled colonies. No differences were found between the share of colonies that had been identified as Nosema-infected on the basis of an analysis of only the live or dead bees (46% versus 46%). Laboratory examination of both types of bee samples can improve the reliability and accuracy of spore counting for the diagnosis of Nosema spp. infection in spring. The introduction of this sampling strategy in routine laboratory diagnostics can be considered as an alternative to the application of more sensitive PCR methods or sampling a higher number of live bees

A Comparative Study of Environmental Conditions, Bee Management and the Epidemiological Situation in Apiaries Varying in the Level of Colony Losses

Explaining the reasons for the increased mortality of the honey bee (Apis mellifera L.) in recent years, in Europe and North America, has become a global research priority in apicultural science. Our project was aimed at determining the relationship between environmental conditions, beekeeping techniques, the epidemiological situation of pathogens, and the mortality rate of bee colonies. Dead bee samples were collected by beekeepers from 2421 colonies. The samples were examined for the presence of V. destructor, Nosema spp. (Nosema apis and Nosema ceranae), chronic bee paralysis virus (CBPV), acute bee paralysis virus (ABPV), deformed wing virus (DWV), and Israeli acute paralysis virus (IAPV)

Amitraz marker residues in honey from honeybee colonies treated with Apiwarol

Amitraz is a formamide exhibiting both acaricidal and insecticidal activity and is frequently used by beekeepers to protect honeybee colonies against Varroa destructor mites. The aim of this apiary trial was to evaluate the impact of honeybee colony fumigation with amitraz on the level of contamination of honey stored in combs

Clostridium perfringens spores in Polish honey samples

The aim of this study was examination of honey samples collected from apiaries situated in all Polish provinces for occurrence of Clostridium spp., especially C. perfringens

Development and evaluation of a core genome multilocus sequence typing scheme for Paenibacillus larvae, the deadly American foulbrood pathogen of honeybees

Paenibacillus larvae is the causative agent of the fatal American foulbrood disease in honeybees (Apis mellifera). Strain identification is vital for preventing the spread of the disease. To date, the most accessible and robust scheme to identify strains is the multilocus sequence typing (MLST) method. However, this approach has limited resolution, especially for epidemiological studies. As the cost of whole-genome sequencing has decreased and as it becomes increasingly available to most laboratories, an extended MLST based on the core genome (cgMLST) presents a valuable tool for high-resolution investigations. In this study, we present a standardized, robust cgMLST scheme for P. larvae typing using whole-genome sequencing. A total of 333 genomes were used to identify, validate and evaluate 2419 core genes. The cgMLST allowed fine-scale differentiation between samples that had the same profile using traditional MLST and allowed for the characterization of strains impossible by MLST. The scheme was successfully used to trace a localized Swedish outbreak, where a cluster of 38 isolates was linked to a country-wide beekeeping operation. cgMLST greatly enhances the power of a traditional typing scheme, while preserving the same stability and standardization for sharing results and methods across different laboratories

Risk indicators affecting honeybee colony survival in Europe : one year of surveillance

The first pan-European harmonized active epidemiological surveillance program on honeybee colony mortality (EPILOBEE) was set up across 17 European Member States to estimate honeybee colony mortality over winter and during the beekeeping season. In nine Member States, overwinter losses were higher and statistically different from the empirical level of 10 % under which the level of overwinter mortality was considered as acceptable with usual beekeeping conditions. In four other countries, these losses were lower. Using multivariable Poisson regression models, it was showed that the size of the operation and apiary and the clinically detected varroosis, American foulbrood (AFB), and nosemosis before winter significantly affected 2012-2013 overwinter losses. Clinically detected diseases, the size of the operation and apiary, and the non-participation to a common veterinary treatment significantly affected 2013 summer losses. EPILOBEE was a prerequisite to implement future projects studying risk factors affecting colony health such as multiple and co-exposure to pesticides