A new scientific review on the insecticidal potential of cannabis concludes that it’s “proved to be a promising plant in terms of mortality and evidenced effects on insect fertility, birth rates, and adult emergence”—findings that could one day offer the possibility of new products to help manage insects that spread deadly diseases.
The paper, from authors at the Universidade do Sul de Santa Catarina and the Universidade Estadual de São Paulo, in Brazil, looked at experimental studies “describing the toxic effects of Cannabis on eggs, larvae, pupae, and adult vector insects,” specifically four types of mosquito and one flea species.
While the researchers said the study “revealed a potential insecticidal effect” of cannabis essential oils, extracts and nanoemulsions, they also noted that available research on the issue is slim. For most insect species, there was only a single study available, and the experiments were inconsistent in terms of product formulations and methodology.
“Different Cannabis formulations showed an insecticidal effect on the developmental stages of five species of medically important insects,” the report says, noting that findings showed the products showed “evident” potential in killing eggs, larvae, pupae and adults.
“As to the action of Cannabis on the reproductive patterns, the potential use of this plant that has ovicidal, larvicidal, pupicidal and adulticidal properties is evident, but also with regard to aspects of fecundity, fertility, birth rate and adult in-sect’s emergence.”
“The larval phase was the most studied; it was approached in all the articles reviewed and taking into account all the Cannabis formulation formats,” authors added. “However, we ought to clarify that despite the reported Cannabis insecticidal action on this insect vectors’ stage of development, there are still few studies that have approached the effect of this plant on the vectors’ larval stage that would allow an effective conclusion considering each formulation.”
The study, published in the Revista da Faculdade de Ciências Médicas de Sorocaba (Magazine of the Faculty of Medical Sciences of Sorocaba), also noted that in terms of available research on the plant’s effects on insect reproductive parameters, “the lack of data becomes indisputable.”
“Cannabis has been a promising plant in terms of insect vector mortality; it has also evidenced effects on insects’ fertility, birth rates and adults’ emergence,” authors concluded. “Therefore, further investigation is crucial to elucidate the role of Cannabis against insects of medical importance as well as to expand our knowledge about the plant’s toxic action, and also to explore its potential in insect vectors’ control strategies.”
The review comes on the heels of a separate study published this summer that found that hemp leaf extract containing CBD could be a promising natural insecticide. The extract effectively killed larvae of mosquitoes that spread dengue, Zika and yellow fever, that research found—including one variety of the insect that’s resistant to conventional insecticides.
Authors from Ohio State University wrote that CBD “appears to be the principal active ingredient responsible for larvicidal activity.”
The findings touch on another possible application of hemp in the agricultural sector, where the plant is already being used in a number of ways.
In February, for example, an organization of livestock feed control officials voted to allow commercial farmers to begin using hemp seed meal as food for egg-laying hens. Under the new policy, which was recommended by the Food and Drug Administration (FDA), hemp meal can account for up to 20 percent of hens’ diet.
The Food and Drug Administration (FDA) sent warning letters in 2022 to a series of businesses marketing CBD products for animals, cautioning that there’s a “lack of data on what levels of potential residues are safe for a person consuming the foods that come from CBD-treated animals.”
Last April, however, the U.S. Department of Agriculture (USDA) found that cows that are fed hempseed cake retain very low concentrations of THC and CBD in their bodies, indicating that meat products from hemp-fed cattle are safe for human consumption.
Another federally funded study published in 2022 found that feeding cows hemp in fact reduces their stress levels. Researchers have also previously looked into how CBD affects stress and pain in horses.
Meanwhile, the U.S. Department of Agriculture (USDA) earlier this year said a genetically modified version of hemp produced by researchers in Wisconsin “may be safely grown and bred in the United States” and is “unlikely to pose an increased plant pest risk compared to other cultivated plants.”
The hemp variety, dubbed “Badger G,” does not produce THC or CBD but is designed to have higher levels of the cannabinoid CBG. It’s at least the second type of genetically modified hemp to get the OK from regulators after another modified plant, which produces lower levels of THC and CBC, was approved in October.
Photo courtesy of Chris Wallis // Side Pocket Images.
A new scientific review on the insecticidal potential of cannabis concludes that it’s “proved to be a promising plant in terms of mortality and evidenced effects on insect fertility, birth rates, and adult emergence”—findings that could one day offer the possibility of new products to help manage insects that spread deadly diseases. The paper, from Read More