Sustainable solutions to problems affecting bee health

Both wild and managed bees are essential for the production of specialty crops in New York. Apples, one of New York's most valuable crops, depend entirely on the pollination services of bees. 

But bees are vulnerable: Reduced natural habitat and increased pesticide use negatively impact the abundance of wild bees in eastern apple orchards. Fungicides, in particular, have a negative impact on wild bee communities. Although fungicides have low direct toxicity to bees, fungicides may be disrupting the microbial communities that feed bee larvae. When solitary bees create nests to lay eggs, the pollen and nectar they gather to feed their larvae host a diverse community of bacteria and fungi – known as the brood cell microbiome. Fungicides may be negatively impacting this microbiome in ways that harm bee larval development. 

This project explored how fungicides and other agrochemicals impact the brood cell microbiome of Osmia cornifrons, commonly known as the mason bee, and how changes in the microbial community influence bee larval development. In 2020, we conducted a series of experiments to determine how a widely used fungicide – cyprodinil – at three dosage levels changes the normal progression of larval development and whether the fungicide impacted the microbial community of the pollen upon which these larvae are feeding. In 2021, we conducted similar experiments with two other widely used fungicides – difenoconazole and captan – at two dosage levels.  In 2022, we conducted a field experiment to determine the effect of proximity to pesticide usage in natural environments.