Home Computer device The device detects the “scent imprints” of pests: USDA ARS

The device detects the “scent imprints” of pests: USDA ARS

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Contact: Jan Suszkiw
Email: [email protected]

January 11, 2022

A team from the Agricultural Research Service (ARS) and university scientists have developed an electronic nose to detect whitefly infestations on tomato plants.

The “E-Nose” works by detecting a specific cocktail of chemicals, called volatile organic compounds (VOCs), that tomato plants release into the air when attacked by whiteflies. In nature, these chemicals put other plants on high alert. Scientists hope the electronic nose will also alert growers so they can refine their use of whitefly killer insecticides, biological control agents like parasitic wasps, or other measures.

According to Heping Zhu, an agricultural engineer at the ARS Application Technology Research Unit in Wooster, Ohio, which co-developed the E-nose with collaborators from Ohio State and the University of Tennessee-Knoxville, whiteflies are the major insect pests in the United States. market tomatoes, which were valued at $ 721 million in 2020.

Left unchecked, adult whiteflies and their immature pupae probe the undersides of the leaves of tomato plants for sap, causing them to turn yellow, curl or drop. Feeding whiteflies can also cause fruit to ripen unevenly and transmit viral diseases that further weaken plants.

Monitoring for whiteflies typically involves checking a threshold number of pests per leaf on a sample of plants or captured in sticky traps, both of which are time consuming processes.

But, the scientists wondered, what if plants could alert growers themselves and in real time?

An electronic nose that detects whitefly infested tomato plants could help greenhouse growers plan their pest control use. Graphic by Heping Zhu, ARS, and Shaoqing Cui, Ohio State University.

To this end, the researchers designed a prototype electronic nose device the size of a shoebox that could operate in the greenhouse. According to Zhu, the device mimics the smell of mammals and the brain’s ability to recognize certain smells. But instead of a nasal passage, receptor cells, and olfactory bulb, the E-nose uses gas sensors, data acquisition modules, and other components.

A key feature of the E-nose is a nerve-like circuit board that helps convert VOC samples from the air into digital signals. These signals are in turn transmitted to the “brain” of the system, a mathematical algorithm programmed to recognize specific types and concentrations – or “scent imprints” – of VOCs that tomato plants give off when attacked.

In greenhouse tests, the E-nose displayed the VOC fingerprints of these plants as different lines with different colors that rose sharply and steadily to the right of an LED screen. In addition, the system distinguished the scent imprints of tomato plants infested with whitefly from those not infested, as well as plants whose leaves were punctured with pins for comparison.

With further testing and development, the E-nose could give greenhouse growers another monitoring tool to use in deciding where, when and how to best suppress whitefly infestations before they reach economically damaging levels. . In addition to whiteflies, E-nose has also successfully detected aphids infesting tomatoes and pests of other greenhouse crops.

“The future E-nose system can be designed as a portable device allowing growers to take samples from individual plants,” Zhu said. “It can also be designed as a computer-controlled cloud network system that consists of several smart sensors placed at different locations in the greenhouse, so that the computer can automatically collect samples and monitor infestations 24 hours a day.”

Details of the team’s findings were published in the October 2021 issue of Chemosensors and in the August 2019 issue of Sensors.

The Agricultural Research Service is the principal in-house scientific research organization of the United States Department of Agriculture. On a daily basis, the ARS focuses on solutions to agricultural problems affecting America. Every dollar invested in agricultural research has an economic impact of $ 17.