The deadliest flower in the insect world is a lifeline to farmers—and the planet

Gilgil, Kenya — The deadliest flower in the insect world is soft to the touch. Each morning in the hills above Kenya’s Great Rift Valley, the white petals of the pyrethrum plant become laden with dew. To the people who pick them, the flower is utterly harmless. But bugs beware: Its yellow center contains a natural toxin that can kill them in seconds.

Discovered in Persia around 400 B.C., the flower produces an active ingredient, pyrethrin, that can be extracted and used to create natural insecticides that farmers spray on crops to protect them from mites, ants, and aphids without harming anyone’s health. Herders rub pyrethrin ointments on their cattle to repel flies and ticks.

In its most common applications, pyrethrin paralyzes pests by attacking their central nervous systems. “If you spray an insect with pyrethrum, for the first 30 seconds it goes mental, incredibly hyperactive, then it falls to the floor,” explains Ian Shaw, managing director of the pyrethrum producer Kapi Limited.

Simply growing Chrysanthemum cinerariifolium near your home may be enough to repel parasite-carrying sand flies, whose bite can spread the skin disease leishmaniasis, which affects nearly one million people globally, including many throughout Kenya. The resulting rash can eat away at people’s faces and become fatal if left untreated.

Pyrethrin has also become a powerful tool in the global fight against mosquito-borne diseases like malaria, a parasite that sickens more than a million people and kills more than 400,000 each year, many of them in Kenya. Manufactured in spiral-shaped discs known as mosquito coils, they emit a shroud of smoke like incense that repels mosquitoes but is harmless to humans.

“Pyrethrin is the most important insecticide in the world,” says Joel Maina Kibett, chief agriculture officer of Nakuru County, a three-hour drive north of Nairobi, Kenya’s capital city. “It is natural, organic, and it has no environmental effects. And it is user friendly.”

For Kibett, the delicate flower also has a special place in his heart for a very personal reason: It paid for his education and made his career. Growing up in Bomet County, in western Kenya, Kibett and his siblings picked the flowers on the family farm. “It was exciting because as young kids your parents would tell you, ‘If you fill this container I’m going to buy you a sweet.’ So we were competing,” he says.

Because flowers can be harvested every two weeks, they generate a stable income for growers nearly year-round. And they tend to grow exceptionally quickly immediately following both of Kenya’s rainy seasons, earning farmers a twice-yearly bonus. Kibett’s parents dried the flowers and sold them to Kenya’s state-run pyrethrum monopoly, using the money to pay the children’s school fees and later, Kibett’s university degree.

“It brought a lot of good things to our villages,” Kibett says. Half a dozen butcheries opened up shop, because people could use their pyrethrum earnings to buy meat.

Learning from pyrethrum’s past

Back when Kibett was growing up in the 1970s and ‘80s, Kenya grew nearly all of the pyrethrum in the world. British colonizers brought it to Kenya in the late 1920s, and by 1940 Kenya had replaced Japan as the world’s leading pyrethrum producer. By the early 1960s it had become Kenya’s third-largest crop, after coffee and tea, supplying more than 70 percent of the pyrethrum in the world and employing some 200,000 farmers.

When Kenya declared independence in 1963, pyrethrum was so important that Kenya’s Coat of Arms featured several of the white and yellow flowers alongside a Masai warrior shield and underneath the feet of two lions. To this day, all Kenyan children learn about pyrethrum in school as part of the national curriculum, according to Immaculate Maina, who oversees Nakuru County’s agriculture, livestock, and fisheries.

Production peaked in the 1980s, but in the 1990s, the industry began a rapid decline and collapsed completely, taking rural economies down with it. Kenya’s state-owned monopoly, the Pyrethrum Board of Kenya, had prevented other private companies from entering the market, making Kenya unable to compete with countries like Australia, where private pyrethrum companies thrived, according to the World Bank. The board also fell behind paying farmers for their flowers and eventually stopped paying at all. Many growers waited months to get paid. Desperate, many had no choice but to switch to other, less lucrative crops. Others lost their farms.

“When the sector went down, not only was my family affected, but also my village,” says Kibett. All six of the butcheries in Kibett’s village disappeared. “No one was buying meat anymore. Hotels and restaurants, shops selling clothes” all shuttered. Some families were not even able to feed themselves. “What happened was a disaster.”

It took until 2018 for the Pyrethrum Board to clear its debt to growers. Now, as more chemical pesticides are being banned and demand rises for pyrethrum to make a natural insecticide, the industry is staging a comeback.

“We in the agriculture office looked back and realized that this flower had been propping up many households,” says Kibett. “Most of us became what we are because of that flower. We had a nostalgia for it. We remember seeing beautiful landscapes covered with white sheets of flowers. We have done it before, and the results were very good. And we have the knowledge. We have the existing infrastructure.”

In 2017, Nakuru’s county government, along with a half-dozen private pyrethrin companies, began distributing pyrethrum seedlings to 15,703 farming households, which already are generating income for more than 100,000 Kenyans.

“In total, we have given out 23.3 million seedlings since we started the revival of the sector,” Kibett says. “And that is our story in just four years.”

Good soil, bright sunlight, and geothermal steam 

Kenya’s central highlands are perfectly suited to growing pyrethrum, which thrives in high altitudes above 5,000 feet, (1,525 meters.) The flower also grows easily on steep slopes.

“Here we have a good combination of sunlight and soil that helps us to get the lovely flowers out,” Maina says.

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The hills of Nakuru County, Kenya’s leading pyrethrum producer, are also situated over Kenya’s abundant geothermal steam reserves, which one company uses to dry the flowers more quickly so as to preserve more of their pyrethrum, which can diminish when farmers leave them to dry in the sun.

On her one-acre farm, Salome Wangari Mbugua spent a recent Saturday picking the tiny, white blossoms off of rows of newly planted pyrethrum. Like Kibett, Mbugwa also helped harvest pyrethrum as a child. By the time she married and had kids of her own, the flower was nowhere to be found. She grew potatoes and maize. Damage from pests and flooding too often left her cash poor, and there were times when she could scarcely feed her children.

So in 2019 when a new, private pyrethrum company came to her village offering seedlings, Mbugwa jumped at the chance. Now, in just two months, Mbugwa earns as much from pyrethrum as she did from potatoes in an entire year. She says she’ll use her new income to “clear my small debts, and my children will have a better life.” She’ll buy a dairy cow, so that her children always have fresh milk to drink, and never go hungry again. Her 11-year-old son, David Muni Mbugwa, noting his mother’s success, wants to become a farmer, too. “My children are a great help to me,” says Mbugwa in the local Kikuyu language. “They even remind me the time is ripe to pick. Because they know how it is benefiting them.”

Still, farming pyrethrum remains challenging. Growing a single acre requires 22,000 seedlings at a cost of 88,000 shillings, or $850—a price still well out of reach for many of Mbugwa’s neighbors. And, even though pyrethrin extract protects other plants from insects and pests, the flower can itself suffer from thrips that puncture the leaves or nematodes that penetrate the roots, sucking up water and nutrients. Ironically, both pests can be treated with chemical sprays, which many farmers also cannot afford.

Each week, Beatrice Muthoni Thumbi, a field officer for one of Kenya’s larger Pyrethrum producers, travels from farm to farm recruiting farmers to switch back to growing the plant. She still faces tough grilling from those who have not forgotten the hard times when they didn’t get paid. They ask: Will your company survive? Will you still be buying our flowers 10 years down the line? Will you pay us on time? Muthoni assures potential clients those days are in the past. It helps that her company pays farmers quickly using a popular digital mobile money system.

On a recent afternoon, Mbugwa cheered as she watched her phone light up with a deposit of 5,198 shillings, or about $48—three days after harvest. The money will buy Josephine, her 19-year-old daughter, a new smartphone and help pay her college tuition.

“You can literally hear the sound of the money coming in,” jokes Simon Kariuki, an agricultural officer for Nakuru’s Gilgil Subcounty.

Back to its natural roots 

As the industry regains its footing, new markets for pyrethrin may hasten its recovery. Chemical pesticides have faced increasing criticism and have been blamed for the so-called insect apocalypse, including the global decline in honeybees. Some have been shown to decimate certain bird populations and destroy aquatic ecosystems by poisoning plankton and fish. One class of pesticides known as neonicotinoids may be harmful to lizards, as well as mammals such as mice, rabbits, and deer. A 2019 study in Costa Rica found that chemical pesticides may even be contributing to an increase in mosquito-borne disease by poisoning mosquitoes’ natural predators.

Today, “developed countries are imposing maximum residue levels—to limit the amount of chemicals farmers can spray onto crops,” explains Shaw. Pyrethrin, which degrades naturally under sunlight and heat, is an environmentally friendly alternative, because “after 24 hours, nothing remains.”

Studies are currently underway to determine whether pyrethrin could be used to kill destructive desert locusts that are decimating crops across East Africa. Swarms can grow to 70 billion locusts and can consume up to 300 million pounds of crops in a single day. Kariuki, the agricultural officer, was assigned to track the pests and recalls seeing a swarm near Mbugwa’s farm that was so dense it clouded out the light of the sun.

To fight the locusts, Kenya has used chemical pesticides that can leave residues on crops for as long as six months, says Shaw, who adds that pyrethrin might soon provide a natural, harmless alternative against locust plagues. A recent University of Nairobi field study of a pyrethrin-based spray showed it killed more than 96 percent of desert locusts in 24 hours. Since much of the world’s pyrethrin was once produced right here, in Kenya, Shaw sees growing pyrethrum as a potentially perfect fix.

"Desert locusts are a Horn of Africa problem," Shaw says. "And pyrethrum is a Horn of Africa solution."