{"id":41767,"date":"2026-06-11T00:01:06","date_gmt":"2026-06-11T04:01:06","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=41767"},"modified":"2026-06-09T11:45:47","modified_gmt":"2026-06-09T15:45:47","slug":"adding-to-wide-body-of-science-study-finds-pesticide-residues-in-honey-bee-colonies-cause-acute-mortality","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2026\/06\/adding-to-wide-body-of-science-study-finds-pesticide-residues-in-honey-bee-colonies-cause-acute-mortality\/","title":{"rendered":"Adding to Wide Body of Science, Study Finds Pesticide Residues in Honey Bee Colonies Cause Acute Mortality"},"content":{"rendered":"

(Beyond Pesticides<\/em>, June 11, 2026) A study of honey bee colonies in Florida and California, published in Environmental Toxicology and Pharmacology<\/em><\/a>, finds elevated mortality from pesticide residues, including those that have been documented to threaten pollinators<\/a>. As the authors describe, \u201cWhile bees die from multiple, often interacting, stressors, here we show single contributors at levels capable of causing acute harm.\u201d The presence of miticides, fungicides, herbicides, and insecticides within the bee colonies, including in the bodies of dying bees, further highlights pesticides as drivers of bee declines.<\/p>\n

By sampling both dying bees and in-house bees for chemical residues, the researchers are able to compare symptomatic colonies and control colonies. The authors note, \u201cOur findings differ from previous screenings, which cast a broad net, screening agrochemicals in colonies nationwide, and not necessarily from impacted operations.\u201d This study, however, shows the presence of specific pesticide residues in commercially managed colonies after die-off incidences. The neonicotinoid insecticide imidacloprid<\/a>, in particular, is widely detected and found in high levels, with the researchers identifying the compound as the largest contributor to bee death.<\/p>\n

Background<\/strong><\/p>\n

Scientific literature linking pesticides, including neonicotinoids<\/a>, to adverse impacts on pollinators continues to mount, as do the devasting population declines of pollinators and other insects. This \u201cinsect apocalypse\u201d has been reported with one-quarter of the global insect population lost since 1990<\/a>. As professor of biology, researcher, and author, Dave Goulson, PhD<\/a>, University of Sussex, says, the drastic decline in insect populations that is occurring threatens all ecosystems. In an essay in Current Biology<\/em><\/a>, he states, \u201cInsects are integral to every terrestrial food web, being food for numerous birds, bats, reptiles, amphibians and fish, and performing vital roles such as pollination, pest control and nutrient recycling. Terrestrial and freshwater ecosystems will collapse without insects\u2026 we may have failed to appreciate the full scale and pace of environmental degradation caused by human activities in the Anthropocene.\u201d<\/p>\n

As the study authors point out, both managed and wild pollinators deliver crucial ecosystem services, most notably pollination, and interact \u201cacross diverse landscapes to enable reproduction in nearly 75% of the world\u2019s flowering plants.\u201d (See study here<\/a>.) The European honey bee, Apis mellifera<\/em>, is both a wild and a managed pollinator in North America and is considered a generalist pollinator, meaning it visits a wide variety of plant species to feed on nectar and pollen.<\/p>\n

With the reliance on chemical solutions, such as in chemical-intensive agriculture, harmful pest management practices threaten pollinators and overall insect biodiversity. Bees encounter pesticides directly and indirectly as they forage, which can then act synergistically<\/a> (causing a greater combined effect) with other chemicals and stressors (like parasites) to cause declines in health.<\/p>\n

Study Methodology and Results<\/strong><\/p>\n

The researchers screened 132 colonies from 23 commercial beekeeping operations in Florida and California after they experienced heightened colony losses. In sampling bees and their products (wax and bee bread, a fermented mixture of flower pollen, nectar, and bee saliva) for chemical residues, the results show high levels of chemical residues in all colony matrices. The colonies in Florida were sampled during or right after mass bee die-offs and before transport to California while colonies in California were sampled at the start of almond pollination. Most notably, levels of miticides (applied directly by beekeepers), as well as fungicides, were the most abundant for all colonies.<\/p>\n

While residues of herbicides and insecticides varied between colonies, imidacloprid contributes 99.9% to overall hazard quotients (HQ). In finding imidacloprid in high prevalence and high levels in a subsample of dying bees, this highlights \u201ca survivorship bias, where dying bees had active ingredients known to have acute toxicity to bees,\u201d while survivors within the hive did not experience the same exposure and subsequent residues prior to sampling.<\/p>\n

Additional results include:<\/p>\n