Pollinators are vital for sustaining biodiversity and global food production, providing essential ecosystem services valued at billions of dollars annually. Yet, their populations have been declining for decades due to multiple, overlapping stressors, including parasites and pathogens, land-use intensification, pesticide use, and climate change. While each of these threats has been extensively studied, their interactive effects on pollinator health remain less understood. In Chapter I explored honey bee pesticide exposure in relation to landscape composition by analyzing honey samples from local beekeepers across the state of Massachusetts, as well as pesticide contamination from commercial wax foundation—a widespread beekeeping practice that mimic natural honeycomb. We found that pesticide concentrations in honey increased with agricultural land cover and declined in areas with more wetlands. Although overall toxicity remained below established thresholds of concern— we used the U.S. Environmental Protection Agency’s acute contact Level of Concern (LOC = 0.4) as a reference (U.S EPA, 2015)—the synergist piperonyl butoxide showed a strong landscape response, with concentration and toxicity both increasing in agricultural landscapes and declining in wetland-rich areas. Additionally, we found that wax foundation itself exposes bees to a wide array of pesticides, representing an often-overlooked contamination pathway. These findings highlight the importance of integrated land management that protects ecosystems such as wetlands to mitigate pesticide exposure, while also rising awareness of the need for wax foundation standards that better support pollinator health. Chapter II examined the effects of chronic, sublethal exposure to three field-realistic concentrations of the neonicotinoid thiamethoxam (0.5, 1, and 1.5 ppb) on Crithidia bombi infection dynamics in lab reared common eastern bumblebee (Bombus impatiens), using both isolated individuals and microcolonies. Elevated mortality occurred only in the individual trials at the highest concentration (1.5 ppb), resulting in its exclusion in the microcolony experiment. While thiamethoxam unexpectedly reduced parasite infection and transmission, it also led to reduced sucrose consumption, impaired mobility, and diminished brood care. These behavioral disruptions may offset any potential benefits of parasite suppression, illustrating the complex and sometimes counterintuitive consequences of interacting stressors on pollinators. Chapter III investigated how drought stress influences neonicotinoid accumulation in the pollen of three major seed-treated crops in the United States: sunflower (Helianthus annuus), squash (Cucurbita pepo), and cotton (Gossypium hirsutum). We also monitored plant performance through weekly growth metrics such as flower production, corolla diameter, plant height, and vine length. Drought consistently reduced floral resource availability but mostly did not affect pesticide concentrations in pollen. Drought did increase detections of thiamethoxam in sunflower, but from a baseline of zero detections in well-watered and moderate stress plants to three very low detections—under the level of quantification—under drought conditions. Across all crops, we detected diverse pesticide mixtures—including insecticides, fungicides, and herbicides—raising concerns about additive or synergistic effects on pollinators. Importantly, patterns of pesticide accumulation differed substantially among crops, emphasizing the roles of crop physiology, pesticide formulations, and environmental context in shaping pollinator exposure risk. Overall, my research demonstrates that pollinator health is shaped by the combined pressures of pesticides, pathogens, and environmental context. These findings underscore the urgent need for integrated conservation and land management strategies that reduce pesticide contamination at its sources, conserve natural habitats such as wetlands, and build resilience in both managed and wild pollinator populations.