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Delayed by the pandemic for nearly a year, the Kenyan government has at last approved a new natural weedkiller just in time for the rainy season. This alternative to traditional pesticides is based on a locally-growing fungus that will help farmers reap a bigger harvest. With wider government approvals, innovative solutions like this can help solve Africa’s food security crisis and bring hope to millions around the world. 

Linet Onyapidi is one of 600 farmers in Bungoma County, Kenya who is planting maize this season with a new optimism. She is among the world’s first adopters of this biocontrol technology that will inoculate her soil against Striga, a pernicious weed that would otherwise destroy as much as 80 percent of her crop. Gaudencia Teyie, another farmer in neighboring Kakamega County, will see a benefit for her children too: “If my fields were free from Striga, not only could I put more food on the table, but by selling the surpluses of my harvest, I could cover my children’s school fees and basic needs.”

The COVID-19 pandemic has made life harder for smallholder farmers like Linet and Gaudencia, who rely on the food they grow to feed their families. Lockdowns have limited access to seeds and fertilizer and to markets where they can sell their crop surplus, if they have any. The result is a growing food security crisis. The World Health Organization estimates that the number of undernourished people—about 690 million in 2019—increased by more than 100 million in 2020. 

As the world emerges from the pandemic with a new appreciation for biology, biocontrols can play a decisive role. Pests such as insects, weeds, and fungi destroy more than a third of potential crop yield around the world, and the damage is worst—up to half—in sub-Saharan Africa. Striga alone causes billions of dollars of losses for over 40 million smallholding farmers each year. 

Since the 1950s, chemical pesticides have been the standard means of stopping these pests. But today they face an array of unintended consequences: resistant weeds, contaminated environments, consumer backlash, and tens of thousands of lawsuits. Over the course of my career, I’ve studied how to use organisms drawn from the local environment to combat pests. Biology to fight biology – biocontrol.

To tackle Striga, in 2008 I helped launch an international collaboration, now called The Toothpick Project, between scientists from Montana State University and the Kenya Agricultural and Livestock Research Organization. We identified a locally growing fungus that attacks the weed but not the underlying crop, and the results were decisive. In proof-of-concept trials funded by The Gates Foundation, 500 farms harvested an average of 42-56 percent more crops. Every single farmer returned for the second season’s trials.  

David Sands

The next crucial step was distributing the fungus—getting it into farmers’ hands, and then their fields. We hit on a method that was simple and scalable, and which gave our organization its name: toothpicks. Toothpicks could be coated with the fungus and stored in a sterile container until they are delivered to local producers at the village level. The trained producers manufacture a live inoculum by growing the toothpick-carried fungus on a cooked rice substrate. The farmer then sprinkles a pinch of the rice inoculum with each crop seed and watches as her farm springs to life.

The fungus kills the Striga invader underground by preventing it from reproducing and spreading. And unlike Striga-resistant maize seeds, expensive fertilizer, or chemically-coated seeds, the fungus is cost-effective and increasingly accessible through a village-based jobs program that drives local revenue.

This approach has been recognized by the MacArthur Foundation and the UN Development Programme among others. The Kenyan government’s approval represents a watershed moment for biocontrol, underscoring its limitless potential for discovery. We’re using the same approach in Montana to tackle thistle and other weeds that have been known to destroy entire fields and limit the acreage available for agricultural production.

To date, only a handful of biocontrols for weeds have been commercialized globally. It’s an idea whose time has come. With every seed they plant, Linet and Gaudencia are leading a scientific revolution in Kenya. Mobile phones have allowed millions to leapfrog traditional telecom infrastructure through access to the Internet. New mRNA vaccines afford a similar shortcut to protecting people against COVID-19. Biocontrols can do the same for food security, enabling farmers to forge biological solutions to biological problems.



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