Toxic effects induced by individual and combined exposures of glyphosate and POEA in honey bees.
Gao Z, Zhou X, Liu D, Yuan H, Xu X
Pollinators
Every time you spray a glyphosate-based weed killer near flowering plants, the unlisted ingredient making it work—POEA—may be hitting nearby bees harder than the herbicide you think you're applying.
Scientists tested a common weed-killer ingredient called POEA on honey bees and found it was dramatically more harmful than glyphosate—the active ingredient most people worry about. When bees were exposed to both together, the damage was even greater: their digestive systems were injured, their immune defenses dropped, and genes linked to vision and navigation were disrupted. This suggests bees exposed to these products may struggle to find their way back to the hive.
Key Findings
POEA's 48-hour oral LD₅₀ was 51.3 μg/bee, far more toxic than glyphosate alone (LD₅₀ >200 μg/bee), meaning POEA kills bees at a fraction of the dose.
Combined glyphosate + POEA exposure produced a synergistic toxic effect (LD₅₀ 41.5 μg/bee) and caused significantly greater oxidative stress, immune suppression, and detoxification enzyme inhibition than either chemical alone.
Transcriptomic analysis showed co-exposure uniquely activated phototransduction and visual perception pathways, raising concern that bees may lose their ability to forage and navigate effectively.
chevron_right Technical Summary
A common herbicide adjuvant called POEA—found in many glyphosate-based weed killers—is far more toxic to honey bees than glyphosate itself, and the two together are even worse, damaging bees' guts, immune systems, and potentially their ability to navigate home.
Abstract Preview
Pesticide exposure remains a major driver of pollinator population decline. However, there is limited understanding of the combined toxicity of active ingredients and their adjuvants, particularly ...
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