How Listening to the Sounds of Insects Can Help Detect Agricultural Pests

Sep 02, 2024

By Lina Tran and Jessica Yung

On a muggy June morning, Emily Bick winds through a field of knee-high corn, just north of Madison, Wisconsin. It feels like that quiet, anticipation-filled moment before a concert: Tech people are setting up microphones, untangling wires.

She's here for a show.

The star of this particular show is the microphone itself. Research assistants are attaching it to the corn stalks, an innovation that Bick dubbed the Insect Eavesdropper.

Bick, an entomologist at the University of Wisconsin-Madison, researches ways to better detect the agricultural pests that drive serious economic losses worldwide. She says improving these methods could result in using pesticides more strategically — less often, at just the right time.

In the Corn Belt, that's corn rootworm, also known as the "billion dollar bug." The insect feeds on corn roots, limiting the plant's nutrient supply and making stalks prone to falling over.

"We lose 20% of our crop to these pests, so we should probably be doing something if we want to conserve more land for non-agricultural use," Bick says.

A few years ago, an Indonesian sugar factory challenged Bick to develop a method of directly and immediately detecting the moths feeding on its sugar cane. With nearly a hundred square miles of land in production, the factory can only effectively monitor so much acreage. Current methods for pest detection also often require harvesting the plant.

Climate change is bringing new challenges. Bugs are thriving in warmer temperatures and expanding their ranges. In our global society, experts say rapid pest detection will be critical to food production, both in the U.S. and worldwide.

Bick's solution to the problem of pest detection is sound: Eavesdropping on the unique vibrations that an insect makes when it's chewing on a plant to identify the insect itself. The Insect Eavesdropper uses a contact mic, an affordable device that musicians often use on acoustic instruments. A little brass disc sits on a solid object — like corn — and captures the vibrations moving through it, registering each one with an electrical signal.

"When corn rootworm feeds on the roots, the vibrations translate from the root system to the stem," Bick says. "That's where we're picking it up. We're using the plant as the musical instrument, as essentially the outside of a guitar."

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