Herbicides can have lethal and sub-lethal effects on honey bees. A new study, conducted in Egypt and published in the Journal of Apicultural Research, has evaluated, for the first time, the acute and chronic toxicity of a bentazone-based herbicide to honey bee workers. A herbicide that is commonly used in maize and vegetable crops.

The results showed acute oral toxicity, with LC₅₀ values of 4.077, 3.747, and 3.579 mg mL⁻¹ after 48, 72, and 96 hours, respectively. The chronic effects appear to be even more worrying. Following exposure to two sub-lethal doses (1/5 and 1/10 of the LC₅₀ at 96 hours), the researchers reported reduced pollen consumption, decreased acetylcholinesterase activity and protein content in honey bees, and significant damage to the cellular structure of the honey bee midgut.

Go to the scientific paper here.