Packaging Insecticides in Tiny Capsules May Make Them More Toxic

Monday, March 18, 2019

Encasing insecticides in microscopic plastic capsules, a common formulation for many pest sprays on the market, could lead to unintended consequences, according to a new study from Oregon State University (OSU).

Environmental toxicologist Stacey Harper and her team found that a common insecticide in its “capsule suspension” formulation – with molecules of the active ingredient encapsulated in tiny, inert plastic pellets – was more toxic than the same amount of active ingredient delivered straight up in water.

Harper and her doctoral student Matthew Slattery studied a commercial pyrethroid-type insecticide with an encapsulated active ingredient, gamma-cyhalothrin. The insecticide is primarily used in the home and garden for ants, bed bugs, ticks and other insects.

Chemical manufacturers have offered encapsulated formulations of pesticides for more than 50 years, Harper said, because encapsulation is thought to improve the product’s dispersal and durability.

“We need to think about considering encapsulation as an ingredient because of how it alters how the active ingredient interacts with the environment,” Harper said. “Currently, the only testing that’s done after the final formulation are hazards like corrosivity and flammability. But not toxicity. What we’ve found is that encapsulation makes a difference in toxicity and that it is size-dependent.”

Read the complete article at OSU’s website.

NIFA supports this research with the Agriculture and Food Research Initiative.

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Related Information

U.S. States and Territories:
Oregon