PubMed · 2026-04-13
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.
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.