Identify two common insecticide modes of action and a resistance concern.

Identify two common insecticide modes of action and a resistance concern.

• A. Neurotoxic pyrethroids and neonicotinoids; resistance can emerge with repeated use of the same mode of action.
• B. Herbicidal action and fungicidal action with no resistance concerns.
• C. Insect growth regulators and microbial pesticides; resistance cannot develop.
• D. Lipophilic solvents and surfactants; resistance typical.

Answer: (A)

Insecticide modes of action describe how chemicals affect pests, and resistance develops when a single mode of action is used repeatedly. Two common modes of action are neurotoxic compounds that disrupt nerve function in insects. Pyrethroids affect sodium channels in nerve cells, keeping them open and causing prolonged nerve firing that leads to paralysis. Neonicotinoids bind to nicotinic acetylcholine receptors, overstimulating the nervous system and resulting in death. The key resistance concern is that repeated use of the same mode of action applies continuous selection pressure, allowing insects with resistance traits to survive and propagate, which over time reduces control effectiveness. Rotating between different modes of action and integrating diverse strategies helps delay resistance and maintain longer-term control. The other options don’t fit because they describe actions not used as insecticide modes (herbicidal or fungicidal actions) or include statements about resistance that aren’t accurate for insecticides, while lipophilic solvents and surfactants are formulation aids rather than modes of action.

Insecticide modes of action describe how chemicals affect pests, and resistance develops when a single mode of action is used repeatedly. Two common modes of action are neurotoxic compounds that disrupt nerve function in insects. Pyrethroids affect sodium channels in nerve cells, keeping them open and causing prolonged nerve firing that leads to paralysis. Neonicotinoids bind to nicotinic acetylcholine receptors, overstimulating the nervous system and resulting in death. The key resistance concern is that repeated use of the same mode of action applies continuous selection pressure, allowing insects with resistance traits to survive and propagate, which over time reduces control effectiveness. Rotating between different modes of action and integrating diverse strategies helps delay resistance and maintain longer-term control. The other options don’t fit because they describe actions not used as insecticide modes (herbicidal or fungicidal actions) or include statements about resistance that aren’t accurate for insecticides, while lipophilic solvents and surfactants are formulation aids rather than modes of action.