Which pesticide class is most associated with systemic behavior in plants and the risks to pollinators when used as seed treatments?

Which pesticide class is most associated with systemic behavior in plants and the risks to pollinators when used as seed treatments?

• A. Pyrethrins
• B. Neonicotinoids
• C. Organophosphates
• D. Pyrethroids

Answer: (B)

Systemic pesticides are taken up by the plant and move through its vascular system, so every part of the plant can contain residues, including tissues that insects visit for food. When a seed treatment uses a systemic compound, the chemical travels from the germinating seed into new growth and into tissues like pollen and nectar. Neonicotinoids are the class most known for this behavior: they’re designed to be absorbed by the roots and transported throughout the plant, which means residues can end up in pollen and nectar and be encountered by pollinators such as bees. This exposure is tied to a range of adverse effects on pollinators, from sublethal performance issues to broader colony impacts, fueling regulatory scrutiny and precautionary usage. The other options are less associated with systemic movement in plants or with seed-treatment–driven pollinator exposure; they’re typically more contact-acting and do not routinely translocate to nectar and pollen to the same extent.

Systemic pesticides are taken up by the plant and move through its vascular system, so every part of the plant can contain residues, including tissues that insects visit for food. When a seed treatment uses a systemic compound, the chemical travels from the germinating seed into new growth and into tissues like pollen and nectar. Neonicotinoids are the class most known for this behavior: they’re designed to be absorbed by the roots and transported throughout the plant, which means residues can end up in pollen and nectar and be encountered by pollinators such as bees. This exposure is tied to a range of adverse effects on pollinators, from sublethal performance issues to broader colony impacts, fueling regulatory scrutiny and precautionary usage. The other options are less associated with systemic movement in plants or with seed-treatment–driven pollinator exposure; they’re typically more contact-acting and do not routinely translocate to nectar and pollen to the same extent.