Study Finds Hemp Could Serve as a Natural Insecticide
A study supported by the Infectious Diseases Institute and the College of Food, Agricultural, and Environmental Sciences at Ohio State and published in the journal Insects reported hemp leaf extract killed two different strains of mosquito larvae. Both strains are known to cause yellow fever. Spraying the hemp extract, which contains CBD, killed the mosquito larvae within 48 hours. Encouraging was the fact one strain was resistant to common insecticides, and the other was not. The hemp leaf extract insecticide killed both strains.
The researchers identified the components of the hemp extract that killed the larvae. After analyzing the extract with gas chromatography-mass spectrometry and nuclear magnetic resonance, they confirmed that CBD was the primary compound in the hemp extract that was toxic to mosquito larvae.
Mosquitoes carry deadly diseases and spread them by flying across distances and biting people and animals. Once they are flying, mosquitoes are more challenging to control. Mosquito larvae are aquatic organisms found in standing water. Killing the larvae is an effective way of controlling mosquitoes before they can cause disease.
Typical synthetic insecticides have been instrumental in managing mosquito populations. Unfortunately, the overuse of man-made insecticides over decades has led to some mosquito strains developing resistance. Synthetic insecticides may also be environmentally harmful.
The researchers took air-dried hemp leaves, pulverized them into a powder, and soaked them in methanol until the desired CBD concentration was reached. The methanol was removed, and the remaining solution was fed to the mosquito larvae.
The researchers found that it only took a small amount of the hemp extract to kill the larvae strains compared to other natural insecticides. Lead study author Erick Martinex Rodriguez said,
“If you compare the amount of hemp extract needed to kill 50% of the population to other synthetic, conventional insecticides, it is on the high side, but when you compare it side-by-side with other natural extracts we have tested in our lab, only a relatively low amount is required to produce high mortality values in larvae.”
Different hemp extract concentrations caused different mortality rates during the hours it took to kill 100% of the mosquito larvae eventually.
The authors caution that more research is needed to determine how hemp extract interacts with other environmental factors, such as honey bees and other insects and mammals. They also noted that hemp is a more environmentally sustainable crop compared to many different plant alternatives. This means hemp extract insecticide could be produced fairly cheaply.
CBD may have many other undiscovered uses if it can kill mosquito larvae.
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