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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVE NUTRITION FOR HONEY BEE COLONIES TO STIMULATE POPULATION GROWTH, INCREASE QUEEN QUALITY, AND REDUCE THE IMPACT OF VARROA MITES

Location: Honey Bee Research

Title: Impact of Orchard Fungicide Spraying on Lowering the Amount of Symbiotic Fungi in Bee Bread and Its Implications for Reduced Colony Resistance

Authors
item Yoder, Jay -
item Condon, Michael -
item Heydinger, Derrick -
item Hedges, Brian -
item Sammataro, Diana
item Finley-Short, Jennifer
item Degrandi-Hoffman, Gloria
item Olson, Eric -

Submitted to: CRC Press
Publication Type: Book / Chapter
Publication Acceptance Date: May 30, 2011
Publication Date: January 2, 2012
Citation: Yoder, J.A., Condon, M.R., Heydinger, D.J., Hedges, B.Z., Sammataro, D., Finley-Short, J.V., Hoffman, G.D., Olson, E. 2012. Fungicides reduce symbiotic fungi in bee bread and the beneficial fungi in colonies. In: Sammataro, D. and Yoder, J., editors. Honey Bee Colony Health: Challenges and Sustainable Solutions. Boca Raton, FL. CRC Press. p. 193-214.

Interpretive Summary: Bee larvae depend on fungi to produce food (bee bread) from stored pollen as a developmental requirement. In the absence of or lower amounts of such fungi, chalkbrood disease (Ascosphaera apis) occurs, which is the highlight observation and the purpose for this chapter. Bee bread is a competitive environment with close interplay of the fungi that are found there (including Aspergillus spp. [primarily A. niger and secondarily A. flavus], Penicillium spp., Cladosporium spp. and Rhizopus spp.). This select group of fungi is perpetuated preferentially and functions as a natural defense shield (via overcrowding, hoarding resources, production of growth inhibiting antifungals) against fungal brood diseases (chalkbrood and stonebrood, A. flavus), as inferred by in vitro fungal-fungal interaction bioassays. Results from bee colonies within the range of areas sprayed with fungicides had low amounts of bee bread fungi. To improve colony defense against chalkbrood, agents known to suppress growth or kill bee bread fungi (e.g., fungicides, formic acid and oxalic acid miticides, high fructose corn syrup) should be applied judiciously and communication with growers in encouraged concerning timing of direct and nearby fungicide applications so that colonies could be moved if necessary.

Technical Abstract: Bee larvae depend on fungi to produce food (bee bread) from stored pollen as a developmental requirement. In the absence of or lower amounts of such fungi, chalkbrood disease (Ascosphaera apis) occurs, which is the highlight observation and the purpose for this chapter. Beebread is a competitive environment with close interplay of the fungi that are found there (including Aspergillus spp. (primarily A. niger and secondarily A. flavus), Penicillium spp., Cladosporium spp. and Rhizopus spp.). This select group of fungi is perpetuated preferentially and functions as a natural defense shield (via overcrowding, hoarding resources, production of growth inhibiting antifungals) against fungal brood diseases (chalkbrood and stonebrood, A. flavus), as inferred by in vitro fungal-fungal interaction bioassays. Results from bee colonies within the range of areas sprayed with fungicides had low amounts of bee bread fungi. To improve colony defense against chalkbrood, agents known to suppress growth or kill bee bread fungi (e.g., fungicides, formic acid and oxalic acid miticides, high fructose corn syrup) should be applied judiciously and communication with growers is encouraged concerning timing of direct and nearby fungicide applications so that colonies could be moved if necessary.

Last Modified: 10/1/2014