Taking the Bait
By Natalie van Hoose - Published May 18, 2015
Entomologist 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."
Argentine 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.
Hydrogel baits offer novel way to manage invasive ants