Drywood termites, which live hidden inside wooden structures, go through about seven molts during their lifetime. Scientists at UC Riverside discovered that a chemical called bistrifluron can disrupt their ability to form new exoskeletons, effectively eliminating termite infestations in homes. According to a study published in the Journal of Economic Entomology, this chemical can wipe out around 95% of a termite colony without posing risks to mammals.
“This chemical is more environmentally friendly than ones traditionally used for drywood termite infestations,” said Nicholas Poulos, the study’s corresponding author and a Ph.D. student in UCR’s Entomology Department. “It’s specific to insects and can’t harm humans.”
Termites, unlike humans, have external skeletons (exoskeletons) that shield them from environmental threats. These exoskeletons are mainly made of chitin, a substance also found in fish scales, squid beaks, fungal walls, and other biological structures. Chitin gives the exoskeleton both protection and support for muscle attachment.
Before molting, termites must generate new chitin for their fresh exoskeleton. Bistrifluron blocks this chitin production, leaving them unable to grow a new protective layer.
“Once the termites reach a certain stage, they have to molt. They cannot avoid that,” said Dong-Hwan Choe, a UCR entomology professor and senior author of the study. “With a lethal dose of this chemical, they’ll try to shed their old exoskeleton but won’t have a new one ready to protect them.” The researchers noted that the chemical first slows down the termites and reduces their feeding before eventually killing them. This marks one of the first studies exploring how chitin-blocking agents affect drywood termites.
Bistrifluron has already proven effective against subterranean termites, another major pest species, and is now showing promise for native western drywood termites, which are especially problematic in California.
As termites consume wood treated with bistrifluron, they transfer it to others in the colony, resulting in a complete collapse in about two months. While slower than other treatments, it has the benefits of lower toxicity and broader colony reach. “We believe this method of spot treatment can kill a larger colony and spread more easily than current termite control methods,” Choe explained.
Unlike fumigation, which is toxic, disruptive, and does not prevent re-infestation, bistrifluron offers a safer and more lasting solution. “Low-impact strategies like this one will become an attractive option in many cases. Furthermore, the chemical may stay active in the wood for some time, potentially providing protection from future infestations,” Choe added.
“We saw significant differences in the death rates using insecticide alone versus the insecticide plus pinene,” said Choe. “Without pinene, we got about 70% mortality. When we added it in, it was over 95%.”
Next, the team aims to find a safer, more practical way to apply bistrifluron. Currently, it is dissolved in acetone for research, but that solvent is flammable and unpleasant. “We are working to make it more feasible for practical application in real life scenarios,” said Poulos.
This breakthrough could be welcome news for property owners, as drywood termites cause significant structural damage. Native to northern Mexico and California, their territory is expanding due to climate change.
“As we move lumber around the world, the termites are constantly transported to new locations. If they find the climate there acceptable, the problem will spread,” Choe said. “In areas where these termites are common, it’s just a matter of time before homes are infested, so this study is a good initial step toward alternative strategies for controlling them.”
Source:
More information: Nicholas A Poulos et al, Toxicity and horizontal transfer of chitin synthesis inhibitors in the western drywood termite (Blattodea: Kalotermitidae), Journal of Economic Entomology (2025). DOI: 10.1093/jee/toaf064
Journal information: Journal of Economic Entomology
