Scientists from Cornell University are investigating the possibility of using hemp cannabinoids as ingredients in natural pesticides.
The results of previous research suggest that plants began biosynthesizing cannabinoids to protect themselves against herbivorous animals and insects that prey on them.
Will this knowledge make it possible to protect crops in an environmentally friendly way? Cannabinoids protect the plant against pests?
As an evolutionary strategy, cannabinoid biosynthesis almost certainly increased the ability of plants to survive and grow. If this were not the case, natural selection would likely abandon this complex and energetically costly mechanism for plants rather than maintain it for millions of generations.
The independent evolution of cannabinoids in several different plant lineages suggests important functionality. Although the adaptive value of cannabinoid production to plants is not definitively known, accepted theories include protection from herbivores, pathogens, or ultraviolet radiation.
Cannabis C. sativa is believed to have evolved in high-altitude environments, leading many researchers to postulate this latter function of cannabinoids.
However, this theory cannot be said to have been scientifically proven. Cannabinoids as protection against herbivores
However, there is evidence that cannabinoids provide the cannabis plant with protection against herbivores. Some scientists assume that the production of cannabinoids may have been an adaptive response of plants to the expansion of animals that threatened them.
Psychoactive THC would discourage herbivorous mammals from eating cannabis due to the effect it has on the nervous system (other mammals, like humans, have cannabinoid receptors that can be activated by compounds in cannabis). This would result in reduced damage to plants or a change in herbivore preferences.
Cannabinoids as protection against insects
Although insects do not have endocannabinoid systems and, therefore, receptors to which plant cannabinoids could bind, it has been proven that these compounds can affect the insect body in other ways.
Both individual Cannabis C. sativa plants and entire populations of these plants show significant biochemical diversity of cannabinoids. In other words: individual plants or groups of plants produce different concentrations of different cannabinoids.
Differences in cannabinoid concentration have been observed to alter the intake, growth, and behavior of certain insect larvae on detached cannabis leaves. The larvae ate less surface area of CBD-dominant leaves than cannabinoid-free leaves.
The presence of cannabinoids reduces leaf intake even when there are no other food sources available.
The difference in cannabinoid concentration was the most significant variable (e.g. difference in nutrients, etc. was minimized). The effects were similar for acidic forms of cannabinoids, including: CBDA and THCA. Hemp pesticides
Scientists from Cornell University (Ithaca, New York) indicate that cannabinoids derived from hemp may constitute a new basis for natural pesticides.
They cite previous research: Researchers have shown that the Pieris brassicae butterfly can distinguish between leaves sprayed with THC and CBD, and that exposure to cannabinoids affects its egg-laying behavior.
Meanwhile, other researchers found that CBD had larvicidal activity against two varieties of beetle and one variety of moth.
They also reported that they found that a certain moth's larvae preferred to feed on leaves with lower levels of CBD, and that increasing CBD concentrations reduced the size, weight and survival of the larvae.
For balance, fruit flies liked leaves containing cannabinoids, and some ant colonies did not pay attention to the presence of THC in their food.
However, as a general rule, the tendency of many insect species to avoid hemp cannabinoids is so clear that research is being carried out on the possibility of using these compounds as ingredients of natural pesticides.
For this reason, at the Faculty of Agriculture of the above-mentioned Cornell University, research is underway on new, environmentally neutral plant protection products, the ingredients of which are hemp cannabinoids.
Sources:
https://academic.oup.com/hr/article/10/11/uhad207/7311041?login=false
https://www.cannabissciencetech.com/view/hemp-derived-cannabinoids-may-be-new -foundation-for-natural-pesticides-according-to-new-research
