Generales

By: Carlos Olimpo Restrepo S.

An investigation of almost two decades demonstrated that an emulsion of the main alkaloid of the plant is highly effective in eliminating this insect, one of the most damaging to this commercial crop worldwide. Caffeine oleate is useful for this and has also shown potential for another important area of world agriculture.

The treated part of the coffee tree is covered and evaluated a few days later. Photo: Courtesy of the Colloids Group

One of the greatest fears of coffee growers is the coffee berry borer. This tiny insect perforates the beans and generates annual losses estimated at around 500 million dollars worldwide. Although there are increasingly more resistant species of the coffee plant to this and other pests in Colombia, combating the damage caused by this beetle remains a priority for the trade.

 For years, coffee growers have sought to reduce the pest through chemical insecticides or predatory species: biological control. However, in recent years, after two decades of research, Universidad de Antioquia discovered that the best tool to combat the insect is in the coffee plant itself.

 "Since 1999, when we created the Colloids Research Group, attached to the Faculty of Exact and Natural Sciences, we have had a line of study on the formulation of botanical pesticides for the pests that affect the country's commercial crops," said Herley Casanova Yepes, the coordinator of the team and a professor at the Institute of Chemistry.

 Initially, we made emulsions from nicotine, a naturally occurring insecticide. We worked with it for about four years but discarded it because of its high toxicity. It affects not only insects harmful to cash crops but also some mammals, including humans. This sparked the group's interest in other alkaloids, including caffeine, which is very low in toxicity, and bromelain, for making pesticides.

 "We experimented with caffeine on several commercial crops to combat whiteflies or aphids, which are among the most widespread pests in agriculture worldwide. We saw that there was an opportunity to work with coffee as well. At the beginning, it was very solitary work," noted Casanova. He added that they collected the first coffee beans with CBB in 2004. By 2006, they had the first results because caffeine oleate proved effective against CBB.

Coffee oleate is a colloid, that is, an emulsion made from the extract of caffeine, the primary alkaloid found in coffee plants. It is oil-based and obtained from coffee tree seeds. This combination acts as a natural insecticide against the coffee berry borer. Unlike other pesticides, it does not require crop harvesting to stop for a time.

From small to medium scale  

In 2007, the researchers published an article in the Journal of Agricultural and Food Chemistry. This opened the door for them to work hand in hand with the Centro Nacional de Investigaciones de Café (Cenicafé) (National Coffee Research Center), attached to the Federación Nacional de Cafeteros (National Federation of Coffee Growers) and propose a research project. The project was approved and received funding from Colciencias.

"At first, the Cenicafé entomologists doubted and told us that we were wrong because they had done studies that showed that the CBB evolved to tolerate caffeine intake. They did not see why it could eliminate the insect in the form of emulsion, but they opened the door for a new research project," recalled the coordinator of the Colloids Group.

Between 2009 and 2010, during research in controlled environments at UdeA and Cenicafé's headquarters in Chinchiná, Caldas, the group made emulsions and microcapsules of caffeine oleate, which were applied to the  CBB crops that the Federation of Coffee Growers has in that municipality. 

"The pesticide was highly effective in controlling the CBB in the bioassays. In the traditional method with water, the mortality of the insect was 20%. With our emulsion, it was 50% to 55% by that time," said Casanova Yepes.

Tatiana Restrepo, a research professor at the Institute of Chemistry and a member of the Colloids Group, carried out the analysis process by electron microscopy. She followed the interaction between the product and the tiny insect with a high-magnification device. "We needed to study the effect of caffeine oleate on the berry borer at different concentrations. We observed what happened to the insect with each pesticide formulation on a microscale to see the modifications; how its morphology and exoskeleton were affected. We concluded that there was a dissection," said the expert.

Casanova pointed out that the product destroys the insect's exoskeleton, legs and jaws within 24 hours. After two days, more than 80% of the insects in contact with the formulation were killed. After five days, mortality was over 94%.

In 2012, Colciencias approved a new Colloids team project. It began to develop in 2014 thanks to the strategic alliance between Sumicol and UdeA. Sumicol is a company that provides services to different materials and chemical industries. The spin-off Nexentia emerged from this alliance. Spin-offs are technology-based companies derived from other organizations. They offer products and services based on research results and developments protected by intellectual property rights, in this case, those of Universidad de Antioquia. The licensing of those rights can result in royalties.

 "We went from laboratory tests, which was what we did in the previous project, to a larger project, in which the emulsion production went from grams to kilograms, and it was applied on Cenicafé commercial crops in Caldas," explained the researcher.

The project lasted four years and thus proved that caffeine oleate can control the CBB under real conditions. This motivated Colloids researchers to seek a patent for the product. Similarly, a collective article was published in the scientific journal Agronomy last June.

"We proved that caffeine oleate is effective against the CBB, and it is an exciting insecticide from a biological control point of view. It is more expensive than what is currently used in the world to control this insect in coffee crops, but it is very clean. Its toxicity in humans is very low, almost non-existent, and the product is biodegradable, which does not generate barriers to exports.

On the left, untreated berry borer; on the right, an insect that shows the effects of caffeine oleate application. Photo: Courtesy of the Colloids Group

Pioneers in the field  

Until the article in the Journal of Agricultural and Food Chemistry was published in September 2007, the insecticidal potential of caffeine and caffeine oleate had not been reported in scientific studies or research in the world. Since then, the work of the Colloids Group has been mentioned and cited in dozens of specialized academic publications.

This research team and its associates applied for a product patent to the Superintendencia de Industria y Comercio (Superintendence of Industry and Commerce) in 2019 after the studies conducted with Cenicafé between 2009 and 2010 and the development achieved with coffee growers, Sumicol and Nexentia between 2014 and 2018. The product is called Emulsifiable concentrates that contain a supersaturated system of caffeine, fatty acids and surfactants with insecticidal activity.

Although the product formulation is ready, and its effectiveness is currently over 90% on coffee crops affected by the CBB, with great potential to combat other insects in avocados, it is not yet available. Still, the researchers are confident that this could materialize in the medium term.