​​​​Taking the Bait

By Natalie van Hoose​ - Published May 18, 2015

hydrogelsEntomologist Grzegorz Buczkowski holds a beaker of dry hydrogel crystals (left) and the same volume of crystals after they have absorbed water (right).(Photo by Tom Campbell)

Water-storing crystals known as hydrogels can effectively deliver pesticide bait to invasive Argentine ants, quickly decimating a colony.

Pesticide sprays and baits are common tactics for managing pest ants. But sprays can have little long-term impact and carry environmental costs such as chemical contamination of soil and water sources. Baits also present challenges: Ants prefer liquid food to solids, rendering granular baits less appetizing. But liquid baits can be difficult and costly to dispense, maintain and clean up.

Entomologist Grzegorz Buczkowski and fellow researchers tested the ability of hydrogels—crystals that can absorb 300 times their dry weight in water—to deliver liquid bait to invasive ants. They found that hydrogels saturated with a small amount of the chemical thiamethoxam dissolved in sugar water reduced the Argentine ant population in an orchard by about 94 percent in two weeks.

"When you drop hydrogels on the ground next to a colony, the ants really go crazy. It's like a big party," Buczkowski said. "This has great potential for managing invasive ants in other agricultural systems and natural environments. You could treat a whole vineyard using hydrogels."

antsArgentine worker ants feed on hydrogels saturated with sugar water.(Photo by Tom Campbell)

Hydrogels also offer the advantage of selectively targeting ants, unlike sprays, which can kill beneficial insects such as bees and butterflies as well as pests.

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Hydrogel baits offer novel way to manage invasive ants

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