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Title: Fungicide contamination reduces beneficial fungi in bee bread based on an area-wide field study in honey bee, Apis mellifera, colonies

item Yoder, Jay - Wittenberg University
item Jajack, Andrew - Wittenberg University
item Rosselot, Andrew - Wittenberg University
item Smith, Terrance - Wittenberg University
item Yerke, Mary Clare - Wittenberg University
item Sammataro, Diana

Submitted to: Journal of Toxicology and Environmental Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2013
Publication Date: 7/22/2013
Publication URL:
Citation: Yoder, J., Jajack, A., Rosselot, A., Smith, T., Yerke, M., Sammataro, D. 2013. Fungicide contamination reduces beneficial fungi in bee bread based on an area-wide field study in honey bee, Apis mellifera, colonies. Journal of Toxicology and Environmental Health. 76(10):587-600. DOI: 10.1080/15287394.2013.798846.

Interpretive Summary: Bee bread is a primary protein source necessary for the proper development and growth of adult bees and bee larvae. Bee bread is made from bee-collected pollen and converted into a protein source bees rely on for food and to activate food glands. This research explored the effects of fungicides that were sprayed on various orchards over a period of several months, and collected from the same colonies as they were moved from crop to crop. Fungicide spraying of orchard and agricultural crops appears to have the effect of reducing the density of naturally-occurring spores (conidia) in the habitat as well as contaminating pollen, such that the amount of fungi that is carried into the bee colony is less and levels of beneficial fungi are suppressed. Fungicide residues are carried back into the colony via contaminated pollen and by the bees themselves. This paper looked at the amounts of culturable and reported beneficial fungi, yeasts and molds that occur in bee bread from colonies that were being used for pollinating several orchards over four months compared to stationary colonies in Arizona. Pollen collected by bees and made into bee bread was tested for fungicides. We found that many of the fungi normally found was reduced in numbers of fungal isolates grown from bee bread where fungicides were present. The effect this may have on bees is discussed.

Technical Abstract: Fermentation by fungi converts stored pollen into bee bread that is fed to and eaten by honey bee larvae, Apis mellifera. To explore the relationship between fungicide spraying and bee bread fungi, samples of bee bread collected from bee colonies pollinating orchards from seven locations over two years were analyzed for fungicide residues and fungus composition. There were detectable levels of fungicides from regions that were sprayed. Aspergillus, Pencillium, Rhizopus and Cladosporium (beneficial fungi) were the primary fungal isolates found, regardless of habitat differences. Variation amongst colonies, even within the same yard were slight, and included Absidia, Alternaria, Aureobasidium, Bipolaris, Fusarium, Geotrichum, Mucor, Nigrospora, Paecilomyces, Scopulariopsis and Trichoderma. The number of fungal isolates was reduced as an effect of fungicide contamination. Concentrations of fungicide that are applied in the field still permit active colonies with viable bee bread despite low fungus levels, but the beneficial fungus levels were not as high compared to colonies with no fungicide exposure in Arizona.