Spinosad
Spinosyn A and spinosyn D
Spinosad is a biological larvicide derived from fermentation of the soil bacterium Saccharopolyspora spinosa. It is used to kill mosquito larvae in standing water and was the first larvicide registered under the EPA Reduced Risk program.
How it works
Ingested or contacted by larvae, spinosad overexcites the insect nervous system by acting on nicotinic acetylcholine and GABA receptors, paralyzing and killing larvae before they mature into biting adults.
The evidence
Spinosad is a well-evidenced larvicide: laboratory studies show close to 100 percent mortality of Aedes larvae at label rates, and field trials report high larval reduction with up to about 60 days of control per slow-release tablet, though real-world duration varies by species, water conditions, and reflooding.
