The Exposure of Honey Bees to Pesticide Residues in the Hive Environment with Regard to Winter Colony Losses

Abstract

The present studies are the second part of the research project dedicated to finding the causes for increased winter mortality of honey bee colonies. The aim of this task was to investigate incidents of overwintered colonies′ death with regard to the potential interrelation to the exposure to pesticides. The samples of winter stores of bee bread and sugar food (honey or syrup processed by bees), beeswax and bees collected from apiaries with low and high rates of winter colony mortality were searched for acaricides used to control V. destructor and plant protection pesticides. The presence of acaricides used in apiculture has been detected in the 51% beeswax samples. The most abundant acaricide was tau-fluvalinate. The stores of bee bread and sugar food had a similar frequency of plant protection pesticide occurrence, ranging between 50-60%, but the number of active substances and their concentrations were substantially lower in sugar food samples. The most prevalent pesticides in pollen were fungicides (carbendazim and boscalid) and insecticides (acetamiprid and thiacloprid). Only a few pesticides were found in the several dead honey bees. The level of pesticide contamination (frequency, concentration, toxicity) of hive products and bees originating from apiaries with both a high and low winter colony survival rates, was similar, which created a similar extent of risk. Although the multiple varroacides and pesticides were present in the hive environment we not found unequivocal links between their residues and high winter colony mortality.

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

“…Developmental rate decrease and bee survival decrease in individuals treated with amitraz was found by Dai et al (2018). Recent studies by Kiljanek et al (2017), Pohorecka et al (2017Pohorecka et al ( , 2018 indicate a potential problem related to amitraz residues in honey bees and their products, and the relatively low effectiveness of measures performed in colonies with brood could be due to the development of V. destructor resistant strains. The efficacy of amitraz treatments executed in broodless colonies and results of the evaluation varroacidal activity of other veterinary preparations containing amitraz Węgrzynowicz et al, 2017) proves the opposite point of view.…”

“…These data reflect that the action undertaken by beekeepers towards fighting Varroa mites are insufficient. For more than thirty years treatment based on amitraz (formulation Apiwarol® and Biowar 500®) have been used by most beekeepers (Pohorecka et al, 2014), which seriously risks the contamination of apiculture products (Kiljanek et al, 2017;Pohorecka et al, 2017Pohorecka et al, , 2018 and the possibility to select more resistant strains of V. destructor (Pohorecka & Bober, 2007, 2008Maggi et al, 2010;Kamler et al, 2016). Low field effectiveness of the administered drug are frequently caused by incorrectly performed treatment procedures.…”

Amitraz marker residues in honey from honeybee colonies treated with Apiwarol

“…According to the Commission Decision 2004/141/EC, amitraz is no longer approved as an active compound in plant protection products in the EU (3). Tests of beeswax and honeybee analysis also shed light on the issue of amitraz residues as a result of honeybee colony treatment (13, 19).…”

Temporal and Spatial Patterns of Honeybee Colony Winter Losses in Poland from Autumn 2006 to Spring 2012; Survey Based on Self-Selected Samples

“…The results of the work presented here show that the problem of high winter losses in Poland did not have an incidental character, but concerned almost all the winters between 2006-2012, and that such climatic factors as a warm autumn or high precipitation during summer, followed by low temperatures during winter, most probably influenced the spatial distribution of those losses. It would be interesting to compare the spatial distribution of colony losses in Poland with the maps of land use and pesticide application in agriculture, although hitherto Polish researchers (Pohorecka et al, 2012;Pohorecka et al, 2017) have not found any relationship between the high winter colony losses and pesticide content in samples collected from colonies.…”