Agricultural Insecticides Becoming More Toxic to Bees

Penn State University researchers found that over the past 20 years, agricultural insecticides have become more toxic to honeybees when ingested. The scientists identified widespread and increasing use of neonicotinoid seed treatments as the primary driver of the change. Their work also considered geographic patterns of insecticide toxicity, and the study found the highest increases in toxicity in the corn- and soy-growing areas of the Upper Midwest. Although pounds of insecticide applied decreased in most counties, this study revealed that oral-based bee toxic load increased by ninefold, on average, across the United States during the period.