A study by US researchers has found that hemp-derived CBD could be an effective and environmentally friendly insecticide. The study, published in the scientific journal Insects, showed that CBD can kill two types of pesky mosquito larvae at an early developmental stage, within 48 hours.
The research, led by a team from Ohio State University, marks a promising breakthrough in the ongoing fight against insecticide resistance, particularly against mosquito species such as Aedes aegypti, which transmits the deadly yellow fever, dengue and Zika viruses.
“It's really important that we can control these pests at their earliest stages, when they're most vulnerable,” said Eric Martinez Rodriguez, an entomology graduate student at Ohio State University and lead author of the study. Killing mosquitoes at the larval stage, before they can mature and spread disease widely, is essential for effective pest management, he noted.
Stubborn tension
The breakthrough comes as mosquitoes around the world are developing genetic mutations that help them thrive against traditional insecticides, posing a serious challenge to global control programs. A species of Aedes aegypti in Puerto Rico has shown stubborn resistance to a commonly used synthetic insecticide that targets the mosquito's nervous system.
However, CBD has been shown to have the ability to circumvent these metabolic defenses.
Researchers at Ohio State University extracted CBD from dried hemp leaves by crushing them and soaking them in methanol to create a potent solution, and found that even small amounts of the CBD-rich extract were deadly to mosquito larvae.
“What was surprising was how little was needed to be so lethal,” Rodriguez said of the compound's potential as an environmentally friendly alternative to synthetic pesticides, whose overuse often has harmful side effects on the environment.
Natural Insecticides
The discovery is part of a growing body of research into plant-derived insecticides. Previous research from Ohio State University has found that plants in Madagascar have natural mosquito repellent properties, which prompted the team to look into hemp.
Peter Piermarini, a professor of entomology at Ohio State University and co-author of the study, said CBD could be an attractive candidate for broader pest management strategies. “It will be interesting to learn more about how CBD interacts with different proteins in mammals and insects to understand why CBD is safe for humans but not for insects,” he said.
However, Piermarini stressed that more research is needed on how CBD-based insecticides affect non-target species, such as honeybees, which play an important role in pollination and biodiversity.
Further research needed
While the findings are promising, they raise questions about the ecological impacts of widespread use of CBD in pest control. Because mosquito larvae thrive in aquatic environments, the researchers note that introducing CBD-based insecticides to these habitats requires careful examination of how they might affect non-target aquatic species. Controlling pests while protecting biodiversity is a delicate balance, and future studies are needed to assess potential unintended consequences, the researchers added.
Researchers also see potential in improving extraction methods for CBD-based pesticides to make them more efficient and environmentally sustainable, including optimizing the concentration of CBD to make them more effective at lower doses and further minimize ecological impacts.
A biological pesticide revolution?
This study opens up several new research avenues, including the effectiveness of CBD against other insect species that are resistant to traditional pesticides. If CBD can be applied to control a wider range of pests, it could revolutionize the biopesticide industry by providing a natural, environmentally friendly alternative to synthetic chemicals.
Additionally, genetic engineering approaches could potentially enhance the insecticidal properties of hemp, making it an even more powerful tool for pest control.
“Understanding how these natural compounds interact with different insect species will be crucial in developing safe, targeted pest control methods,” Rodriguez said, noting that the ultimate goal is to create solutions that are less harmful to the environment while remaining effective against resistant pests.
The research was supported by the Institute of Infectious Diseases and the College of Food, Agricultural, and Environmental Sciences at Ohio State University. Insects is a peer-reviewed, open-access journal published by the Interdisciplinary Digital Publishing Institute, based in Basel, Switzerland.
