Surveying the intensity of European foulbrood disease outbreaks in honey bee (Apis mellifera ) colonies pollinating specialty crops in Oregon and California

Managed colonies of honey bees, Apis mellifera, are vital for agricultural production. However, these colonies are subjected to a plethora of environmental stressors. As of 2024, these conditions have led to reported outbreaks of European foulbrood (EFB) disease among hives from commercial pollinators operating in specialty crop fields. Losses incurred from EFB infestations in their hives have led to some commercial pollinators to opt out of providing their services to crops such as blueberries ((Vaccinium section Cyanococcus). To further complicate matter, the causative agent of EFB outbreaks, the bacterium Melissoccus plutonius, appears in states such as Oregon to be an aggressive and highly virulent group of atypical variants, leading to devastating impacts to infected colonies. High prevalence and intensity of EFB seen in honey bee colonies pollinating early season specialty crops is an emerging threat to beekeepers and specialty crop growers. Due to these variables and an expected increase in produce demand, growers and beekeepers are anxious for a solution to this problem before this creates a significant impact on an already stressed market. This presentation takes a look at the first year of data collected during our two year longitudinal survey on colonies pollinating specialty crops in both California and Oregon. The presentation will discuss the intensity of EFB outbreaks observed during the survey both by crops and over time. Finally, the presentation will discuss future work as surveys are wrapped up including data analysis and mitigation experiments.