Researchers just made it easier—and cheaper—to confuse crop pests

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For some growers, pheromones provide an attractive alternative. Female insects naturally emit pheromones that attract males to mate. By flooding their fields and orchards with fake pheromones designed to appeal to specific insects, farmers can overwhelm these signals and prevent reproduction. Females then lay sterile eggs, which don’t hatch into hungry caterpillars.

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Synthesizing this chemical smokescreen is nevertheless a complex, expensive proposition. It can cost anywhere from $1000 to $3500 to produce just 1 kilogram of artificial pheromones. Deploying it can cost between $40 and $400 per hectare, depending on the type of pest.

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In a bid to lower costs, Christer Löfstedt, a chemical ecologist at Lund University, and his collaborators in several countries have for the past decade been modifying plants to produce the chemical building blocks needed for synthesizing pheromones. Their crop of choice is Camelina, a flowering plant related to canola with seeds rich in fatty acids—key ingredients in coaxing plants to produce these raw materials.

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In 2017, the team tested this pheromone blend in China. They put pheromone traps on sticks about 10 to 15 meters apart in a plot of the leafy Brassica choy sum. The traps worked just as well as commercial synthetic pheromones, the team reports today in Nature Sustainability. Another test in bean fields in Brazil revealed that a single plantmade pheromone could disrupt the mating patterns of the destructive cotton bollworm (Helicoverpa armigera) just as well as a synthetic pheromone.

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