Semion: Can Plant Communication be the Key to Saving Argentina’s Crops? 

An innovative biotech startup is using nature’s own signals to fight crop-killing insects—without toxic chemicals. 

TUCUMÁN, Argentina –

When dozens of desperate farmers and seed and agrochemical vendors flocked to Victoria Coll’s laboratory in Tucumán, Argentina, she knew her research had finally met its moment. 

It was September 2023, and the visitors were on edge about the corn leaf­ hopper—a four­millimeter­long bug already decimating the grain crops nationwide. Traditional insecticides had failed, leaving farmers facing billions in losses. Coll, a botanist with a doctorate in analytical chemistry, was certain the answer lay in cracking the code plants use to communicate with insects: their scent. 

“Smell is a very universal language, except for between us humans,” Coll says. “Ants and bees, for example, communicate mainly through olfactory cues.” 

Ultimately, Coll made the farmers and vendors powerful allies in the fight against the leafhopper when she became one of the four founders of Semion. The company, a biotech start­up launched in 2023, focuses on restoring crops’ ability to defend against pests. 

Their method consists of spraying the plants with substances that boost their natural defenses, activating genes that make them release odors that change insects’ behavior. Those scents both repel plagues and attract parasitoids, other insects that kill the pests and do not harm the plants. Semion is currently working on pests affecting corn and citrus and, in May, they will finish their on­field trials. They plan to scale up their production later this year. 

Coll always wanted to be a biologist. Before beginning with Semion, she spent more than a decade in Tucumán investigating corn and its interaction with the leafhopper. 

The corn leafhopper transmits four pathogens causing the corn stunt disease, which results in visibly shorter plants, leaves with white streaks and red edges, and smaller ears with almost no grains. The leafhopper also lays eggs in the plant’s bud, leaving open stomata that expose it to drying. 

“When the plant is very infected, there can be up to 50 leafhoppers per plant— it has no chance to survive,” explains Coll, who did much of her research in collaboration with the renowned entomologist Eduardo Virla, with whom she shares the laboratory in Tucumán.

Warnings Ignored, a Crisis Takes Root 

At least since 2005, Virla has been warning people in the agricultural community that Argentina could have a major problem with corn leafhoppers, but no one took him seriously. 

“I told them, the way you are handling things, this is going to blow up at any moment,” says Virla. The corn leafhopper can live up to three months in corn ears. Its depopulation occurs naturally when there is no corn growing. But now, he says, Argentine farmers are growing corn almost all year round. “You have two months at the most without corn. In other words, you are benefiting the bug,” he says. 

Moreover, higher temperatures due to global warming and entire years without frost mean the insects can thrive, even beyond the 30° latitude, where the leafhopper is historically associated. Virla calls the phenomenon “tropicalization.” 

Coll did not fare better. When publishing scientific papers or asking for funding for her investigation, she says people in academia and at agricultural supply companies usually brushed her off, telling her that she should change her object of study as the insect “was not a problem.” 

“No one [but us] was studying the odor produced by the corn plant as it was attacked by the leafhopper,” says Coll. Through a gas chromatographer, she outlined the “volatilome” of multiple corn types—that is, the “aura” of volatile compounds that originate from it, or its odor profile, so to speak. That way, they could learn which of its components attracted the leafhopper, which repelled it, and which attracted the leafhopper’s parasitoid—a wasp that lays its eggs inside the planthoppers’ eggs, interrupting their hatching process. It is called Anagrus virlai, named after Virla himself when its biology was first described in 2018. 

The research Coll and Virla were undertaking would later be instrumental in developing Semion, but at the time, their work fell on deaf ears. 

Lessons From a Citrus Tree 

Unable to move forward with the leafhopper project, Coll moved to Fort Pierce, Florida in 2022 with a Fulbright Fellowship to apply her research to another kind of pest. She had contacted a researcher in the Agricultural Research Service who was also working with hormones and odors to fight a plague: the citrus greening disease, also known as HLB, which can shorten the lifespan of citrus trees from 40 years to 5–7. The disease, caused by bacteria, is transmitted by an insect called psyllid and has no known cure. It is the most serious problem in the Florida citrus industry, reaching more than 90 percent of the crops. 

Working with Alejandro Forlin, an Argentine agricultural engineer, Coll tested her hypothesis in the laboratory and later in Fort Pierce’s Botanical Garden. The psyllid is highly responsive to a specific volatile compound emitted by HLB­infected plants, so the scientists blocked its biosynthesis in citrus trees and stimulated it in “trap crop plants,” which they transported in Forlin’s car. 

“Beautiful aroma—it was in my car for a week,” Forlin wryly recalls. 

The plan worked even better than everyone hoped—after 10 months, the treated plants were 100 percent free of HLB disease, while non­treated ones were 66 percent infected. 

Back in Argentina, Virla and Coll’s warnings were finally coming true. According to the Rosario Stock Exchange, between 2023 and 2024, 12 million hectares of corn were lost to the leafhopper—18 percent of the country’s total crop in 2023­2024, a loss close to $2 billion. 

International news agency Reuters reported on the matter. “Many are going to reduce their hectares of corn to zero,” Aníbal Cordoba, a farmer in northern Chaco province, told them in May 2024. “You normally find leafhoppers in the bud of the plants if you look. But this year you go to the field, and you find clouds of leafhoppers. It’s just crazy.” 

Return to Argentina 

Coll returned to Tucumán with new determination in 2023 and started trials with compounds that trigger the release of odors that repel the corn leafhopper. In August, Gridx Exponential, the most important biotech startup accelerator in Latin America, contacted Coll for the fourth year in a row. They wanted to turn her investigation into a business—in previous years, she had rejected them because she did not feel ready. This time, she accepted. 

Through GridX Exponential, Coll met Emilio Molina, an Ecuadorian who for years had been trying to start a plague control company. “I am a third-generation farmer,” says Molina. “My father is a small banana producer and since I was a little boy I saw a very strong correlation: The more agricultural supplies my father applied to his field, the more money he lost,” he says. A clear cycle repeated itself, he says. New agrochemicals were launched, pests became resistant to them, and then they became obsolete. 

In August 2023, Molina, Forlin, Coll, and an entomologist named Jorge Hill founded Semion. The name means “message” in Greek, referring to the messages transmitted through smell. Virla, the entomologist who first discovered the leafhopper’s parasitoid, works as an advisor to the startup. Today, 14 people are working on the project. 

With financing from Gridx Exponential, they started trials in laboratories and fields throughout Argentina and Paraguay. Forlin drives through the country contacting farmers, who he says are generally eager to participate in the research. Having real farmers testing the compounds in the field is important, Forlin says, because there are things that one cannot prepare for in laboratory conditions—rain, wind, storms, other plagues, and the soil. “The soil is alive and it breathes,” he adds.

In its first year of operation, Semion developed Belion, a compound sprayed directly on the plant that triggers the release of odors repelling the leafhopper and attracting the parasitoids. It also increases the plant’s resilience against insect attacks and disease by enhancing physiological traits like nutrient conductivity, photosynthetic capacity, root mass development, and water use efficiency. 

“Domesticated crops lost some defense mechanisms; others are dormant,” says Molina. “We develop products based on natural compounds to activate them when the plant is under stress or attack, so that it expresses genes that were not expressing themselves.” 

In a corn trial at the agronomy school, the scientists found that “plants with chemical controls had a much larger presence of pests and grew less,” says Semion co­founder and entomologist Jorge Hill. He adds that those treated with Semion’s products had fewer pests, “higher photosynthesis values, and in the end, they ended up producing more.” 

The reason, Coll explains, is the same as why the 2024 corn crop fared so terribly. “Since there were so many leafhoppers, farmers, in their desperation, applied insecticide up to 12 times. And, by doing that, they killed the plague’s natural controller—they killed the parasitoid, and the leafhopper was not even tickled.” 

Semion compounds are also less toxic than agrochemicals, benefiting farmers and consumers, as well as the local environment. 

“The solution [companies are proposing] is more insecticide,” Coll says, adding that Semion is proposing a change of paradigm. They plan to partner with an agrochemical company by November to scale up the production and sell their compounds as a bio­stimulant. 

Apart from all the trials in the countryside and laboratories, Coll has put her research to the test in her house garden. “When I had leafhoppers in my grass, I released parasitoids. It is a biological control that does not deregulate the ecosystem, which has a way of self-regulating,” she says. 

“I don’t kill one single spider.” 

Learn more about Semion.

Author: Facundo Iglesia
Photographer: Anita Pouchard Serra