Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It is a mixture of two chemicals called spinosyn A and spinosyn D. It is used to control a wide variety of pests. These include thrips, leafminers, spider mites, mosquitoes, ants, fruit flies and others.

Spinosad has been registered for use in pesticides by the US Environmental Protection Agency (EPA) since 1997.

Currently, spinosad is found in over 80 registered pesticide products. Many of these are used on agricultural crops and ornamental plants. Others are used in and around buildings, in aquatic settings, and as seed treatments. These products are commonly sprays, dusts, granules, and pellets. Some of these products are approved for use in organic agriculture.

Spinosad is also found in some drugs regulated by the US Food and Drug Administration. These products are used to control head lice on people and fleas on dogs and cats.

Spinosad affects the nervous system of insects that eat or touch it. It causes their muscles to flex uncontrollably. This leads to paralysis and ultimately their death, typically within 1-2 days.

People are most commonly exposed to very low levels of spinosad through their diet. Exposure can also occur if you breathe it in or get it on your skin or eyes. For example, this can occur while applying sprays or dusts during windy conditions. This can also happen after using a product if you don’t wash your hands before eating or smoking. You can limit your exposure and reduce the risk by carefully following the label instructions.

When eaten, spinosad is readily absorbed. Once inside it moves to many areas of the body and is broken down. The majority leaves the body in feces or urine within 1-2 days. Spinosad is absorbed poorly through skin contact.

No. In multiple studies, animals were fed low to moderate amounts of spinosad in their diet for 1.5 to 2 years. No increased incidence of cancer was observed. Moreover, spinosad has not been found to alter or damage genes. As a result of these experiments, the EPA has classified spinosad as not likely to cause cancer.

In one study, dogs were fed low doses of spinosad for one year. Effects to gland and immune cells and increases in some proteins and fats in the blood were observed.

Scientists have also tested whether spinosad causes developmental or reproductive effects in rats and rabbits. In these studies, animals were fed low to moderate doses daily throughout their lives or during their pregnancies. Effects were only observed at the highest doses. These included lower body weights and effects to some organs. Abnormal vaginal bleeding, more difficult labors, and abortions were also observed in some pregnant animals at the highest doses tested. No direct effects to their offspring occurred at any dose level.

The EPA limits the levels of pesticides, including spinosad, allowed on food. Due to this, it is unlikely that individuals would be exposed to spinosad at levels this high through their diet.

Children may be especially sensitive to pesticides compared to adults. However, there are currently no data showing that children have increased sensitivity specifically to spinosad.

Spinosad is practically non-toxic to moderately toxic to fish depending on the species. It is slightly to moderately toxic to aquatic invertebrates. However, spinosad is very highly toxic to eastern oysters. Spinosad is practically non-toxic to slightly toxic to birds, based on studies with bobwhite quail and mallard ducks. It is moderately toxic to earthworms. Spinosad is very highly toxic to bees. However, evidence suggests that spinosad has little or no effect on honey bees and other beneficial insects after sprays have dried.