Natural pesticide potential: Researchers in Japan make discovery for organic farming
25 Mar 2024 --- Researchers at Tokyo University of Science, Japan, have revealed that rose essential oil can act as a safe pesticide for organic agriculture. The oil activates tomato defense genes and attracts herbivore predators that protect the plants from moths and mites.
The researchers claim this discovery, published in the Journal of Agricultural and Food Chemistry, creates opportunities for sustainable pest management worldwide.
According to the researchers, applying chemical pesticides is the method of choice for crop protection, but the damage they cause to the environment and ecosystems, along with the need to increase food productivity, raises questions about the urgent need for safer alternatives.
The availability of plant-derived essential oils could offer a scalable solution to this problem. However, there is a lack of sufficient proven examples to meet the demand.
The use of harmful pesticides is a long-running issue in agriculture. A recent report released by the Pesticide Action Network Europe warned PFAS substances in fruits and vegetables tripled between 2011 and 2021.
In the UK, the government recently approved the use of a previously banned pesticide to treat beet seeds amid a virus spread.
Plant-derived essential oils
Plant-derived essential oils have applications across various industries, including food additives, detergents, cosmetics and pharmacology.
Moreover, these oils have a high safety profile, and their numerous bioactivities benefit human health, the researchers say.
They have also been found to elicit insect-repellent responses by inducing neurotoxic effects. Terpenoids are abundant in plant-derived essential oils and have garnered widespread attention as they can regulate plant defense responses by regulating the expression of defense genes.
For example, soybean and komatsuna plants, when grown near mint, experience a significant improvement in defense properties and become resistant to herbivores. This phenomenon occurs through a process known as “eavesdropping,” wherein volatile compounds are released from the mint plant, which triggers the activation of defense genes, protecting against potential herbivore threats.
Rose essential oil was found to attract herbivore predators that protect tomatoes from pests.
Inside the research
A research team led by Professor Gen-ichiro Arimura from the Department of Biological Science and Technology at the Tokyo University of Science assessed the efficacy of 11 plant-derived essential oils in activating tomato defense responses.
“Essential oils used as fragrances for various purposes contain odor components, which may have the ability to work like volatile compounds in conferring pest resistance. We aimed to investigate the effects of these essential oils on plants’ insect pest resistance,” says Arimura.
The team applied ethanol-diluted solutions of 11 different EOs to the soil of potted tomato plants, performed molecular analyses to study the gene expression inside leaf tissue and observed that rose essential oil increased the transcript levels of the genes involved in plant defense.
Additionally, tomato plants treated with rose essential oil exhibited reduced leaf damage caused by moths, larvae and mites.
Broader applications
The researchers also conducted a field experiment to measure essential rose oil activity in field conditions to explore the possibility of broader application. They observed a 45.5% reduction in tomato pest damage compared to the control solution.
The researchers believe that rose essential oil could serve as a viable alternative to pesticides during the winter and spring seasons when pest infestation is less severe and could potentially reduce pesticide usage by almost 50% during summers.
“Our study suggests a practical approach to promoting organic tomato production that encourages environmentally friendly and sustainable practices,” says Arimura.
“This research may open doors for new organic farming systems. The dawn of potent environmentally friendly and natural pesticides is upon us.”
By Joshua Poole
