Researchers at the University of New Mexico (UNM) have found a way to use lemongrass oil as a lethal weapon against mosquitoes that carry the Zika virus and other diseases.

Given that the use of pesticides on mosquitoes has harmful side effects on humans, the researchers set out to find a natural, cost-effective alternative. Lemongrass oil is well known for its toxicity, so a team at UNM’s Health Sciences Center aimed to find a way to deliver the oil to larvae without polluting water supplies.

They took a Trojan Horse approach: injecting lemongrass oil into yeast cells, a source of nutrients for mosquito larvae. When the larvae ate the yeast, the lemongrass “bombs” were released into their gut, and the result was promising. The larvae started dying within 24 hours. A week later, 100 percent of the larvae had died.

“Yeast becomes a perfect capsule in that it contains the oil and is degraded by enzymes in the gut of the larvae,” said Ravi Durvasula, MD, an infectious diseases researcher at UNM’s Center for Global Health. “Therefore, the oil is delivered inside of the larvae, where it is extremely toxic to the insect.”

The team now is seeking a partnership that could help fund real-world testing of the lemongrass oil. “We need to test this under conditions in urban settings — puddles, tires, cisterns — where a large amount of detritus exists already in the water,” Durvasula said. “We also need to test the approach under large-scale spatial settings in the field.” They also plan to test other essential oils and combinations of oils to see if there might be a more-effective solution.

The researchers say their findings can be applied in developing countries where dengue fever, Zika virus, and other diseases caused by the Aedes genus of mosquitoes are endemic.