Sustainable Agriculture – Pest Control: How Plants Communicate with Scents – Knowledge

Plants cannot run away, but they defend themselves with their scent language. When infested with pests, for example, corn plants use an attractant to attract insects that eat the parasites from their bodies. For this discovery, Ted Turlings receives the Benoist Prize.

At the beginning there was a seemingly not particularly exciting question: How do parasitic wasps find their way to their prey, ie caterpillars on corn plants? Ted Turlings, then a young graduate student in Florida, got to work. And experienced a surprise: Contrary to what was assumed, it was not the parasitic wasps that were looking for prey, “but the plants played the active role,” says the 64-year-old. “Eaten by caterpillars, they gave off an intense scent that was useful Attracted parasitic wasps.”

Pioneering work on the olfactory language of plants

Plants that specifically summon the enemies of their enemies with fragrant cries for help: This finding was completely new in 1990, when Ted Turlings published it. Experts say that Turling’s pioneering work has demonstrated that plants use scents to control pests on themselves.

Beneficial insects that, like parasitic wasps, are attracted to plants’ SOS scents are now widely used in organic farming to combat fruit and vegetable pests. That works well, says Dani Lucas-Barbosa from the Research Institute for Organic Agriculture (FiBL). But she also sees challenges: “We still don’t know enough about when exactly we have to spread the beneficial insects into the fields. It would therefore be helpful to be able to recognize the SOS signals from corn and other plants at the right time and in the right place.”

Sniffing agricultural machines

Researchers like Ted Turlings are on the ball here. Supported by a grant from the European Research Council, the professor at the University of Neuchâtel is developing sensors that can detect plant odors. “In the future, we want to install such odor sensors in robotic agricultural machines. They could then drive over the fields and no longer distribute plant protection products across the board, but rather specifically only to those plants that use their scent to defend themselves against pests.

Worm gel “at least as effective as a pesticide”

The use of pesticides could be massively reduced, says Turlings. Or you could even fight plant pests without using pesticides – with the help of a gel that he and his team developed. The gel contains nematodes, beneficial insects that are normally active in the soil. But in the gel, the worms also act on leaves: in field tests with corn plants and pests, the gel proved to be “at least as effective as a pesticide tested for comparison.”

Very soon, however, intelligent sniffing robots with worm gel on board will not be cruising across fields. Developing odor sensors is considered challenging, especially since odors quickly evaporate and mix in the air. But Ted Turlings stays tuned. With the small company Ecorobotix, he is currently testing olfactory agricultural robots in the Yverdon-Les-Bains region – among other things.

But for now he is happy: the biologist says he is “excited and honored” that as a Dutchman he is receiving the prestigious Marcel Benoist Prize in Switzerland.