UC Riverside scientists discovered a new method of termite control using pinene to attract termites to insecticide, offering a non-toxic and cost-effective alternative to traditional fumigation. Credit: Dong-Hwan Choe/UCR
UC Riverside scientists have introduced an effective and sustainable termite control strategy using pinenes to lure termites to insecticide-treated areas, achieving over 95% effectiveness and reducing reliance on harmful fumigation methods.
UC Riverside scientists have discovered a highly effective, non-toxic and less expensive way to lure hungry termites to their doom.
The method, detailed in Journal of Economic Entomology, uses a sweet-smelling chemical released by forest trees called pinene that reminds western drywood termites of their food. They follow the scent to a spot of insecticide injected into the wood.
“We saw significant differences in mortality rates using insecticide alone versus insecticide plus pinene,” said UCR entomologist Dong-Hwan Choe, who led the discovery. “Without pinene, we got about 70% mortality. When we added it, it was over 95%.
Native to North America, western drywood termites are environmentally important. They are attracted to dead wood above ground and consume it with the help of microorganisms in their guts. “They are recyclers,” Choe said. “And they are very common.”
Current challenges in termite control
Unfortunately for humans, insects are unable to distinguish between dead trees and wood used to build houses. Of particular concern in California and Florida, as well as parts of Canada and Mexico, no residence is immune to them. “It’s only a matter of time before termites attack a home, especially in warmer parts of the states,” Choe said.
Fumigation is one of the most common drywood termite control techniques. Houses are covered with tents and then bombarded with gas that kills insects. In the US, California uses this method more than any other state.
Western drywood termites are attracted to pinene, a chemical found released from forest trees. Credit: Dong-Hwan Choe/UCR
The pest control industry is under pressure to find new methods because the chemical, sulfuric fluoride, is both a greenhouse gas and toxic to humans. In addition, fumigation is an expensive process that does not provide lasting protection against termites.
“Even though it’s very thorough, a house can become infested again quickly after the fumigation is over,” Choe said. “Some people smoke every three to five years because it doesn’t protect the structures from future infestations.”
Advantages of localized injection and use of pinene
Localized injection is an alternative strategy to control drywood termites that does not involve gas. Technicians drill holes in the infested wood to reach the termite’s “gallery,” or den, then inject poison into the hole to flood the insects.
“This is a more localized treatment, and in theory, it’s a better strategy when you want to control drywood termites with fewer chemicals. It’s less expensive and the treated wood can also stay protected from future infestations,” Choe said.
The challenge with localized injection is finding out exactly where the bugs are hiding. Typically, this method uses a contact-based insecticide, meaning the insects must touch the poison for it to work.
Using an attractant like pinene eliminates the need to hunt for termites. “Even at low concentrations, pinene is good at attracting termites from a distance,” Choe said.
“We don’t think it’s working as a pheromone,” Choe said. “We think the smell is more related to their food. Smells good…dinner time! That’s the concept we had in mind.”
The insecticide they used, fipronil, is also used to control ant infestations. May be toxic to aquatic insects and pollinators if released into the environment. In this case, it is injected into the wood, so the chances of off-target effects are low.
Choe’s lab generally studies the chemical communication systems of urban insect pests to develop strategies like this for western drywood termites.
“Our study shows that if you understand insect behavior better, that’s interesting in itself,” Choe said. “Then there are also important implications for more effective pest management, so we can use fewer chemicals without compromising efficacy.”
Reference: “Potential Use of Pinenes to Improve Localized Insecticide Injections Targeting the Western Drywood Termite (Blattodea: Kalotermitidae)” by Nicholas A Poulos, Chow-Yang Lee, Michael K Rust, and Dong-Hwan Choe, 16 May 2024, Journal of Economic Entomology.
DOI: 10.1093/jee/toae101