Dimefluthrin

Dimefluthrin is an insecticide that exhibits contact toxicity against invasive red fire ant workers. It can spread horizontally among these ants, leading to secondary mortality in those exposed. As a neurodevelopmental toxin, Dimefluthrin reduces the activity of acetylcholinesterase (acetylcholinesterase), impairing neurotransmitter function.

Dimefluthrin, at concentrations of 0.325-12 μg/mL over 24 hours, effectively exterminates large red imported fire ant workers, with an LD50 of 1.57 ng per ant. It exhibits a rapid knockdown effect on these ants, with a KT50 value between 0.5 and 5 μg/mL. A solution of Dimefluthrin at 30-60 μg/mL can be efficiently transferred among red imported fire ant (Solenopsis invicta) workers; at a concentration of 60 μg/mL, it results in a mortality rate exceeding 98% among secondary exposed ants within 24 hours and up to a 99.33% mortality rate among tertiary exposed ants within 48 hours.

Dimefluthrin (0.2-0.8 μg/mL; 72 h) induces concentration-dependent neurodevelopmental damage, vascular dysfunction, neurotransmission disorder, and inhibition of motor behavior in zebrafish larvae. Significant effects are observed at doses as low as 0.2 μg/mL, with near-complete inhibition of CNS axon bundle growth at the highest test dose of 0.8 μg/mL. These motor effects can be reversed by Bromocriptine.