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Fourteen-year-old Sirish Subash — a ninth-grader from Snellville, Ga. — was crowned the winner of the 2024 3M Young Scientist Challenge contest in St. Paul this week. He picked up a cash prize of $25,000 and the lesson that moms are always right. 

Subash’s invention, Pestiscand, is a handheld device he designed for at-home use to detect pesticide residue on produce without damaging the food. It measures the wavelength of light reflecting off of fruits and vegetables and uses a machine-learning model to analyze the data. Users download a phone app, point Pestiscand at the produce, tap the scan button and voilà, they see if their apple or spinach needs another rinse. 

“Oftentimes there are these residues from pesticides that are found on produce. If we could detect them, then we could ensure that we weren't really consuming them,” Subash told MPR News. “That’s the main goal of Pestiscand, to help people ensure that they aren’t consuming pesticides used so they can avoid any associated health risks.” 

The idea for the invention was sparked from a conversation between Subash and his mom. 

“My parents always insist that I wash my produce before consuming it. I wondered, how necessary is this really, and how effective is the washing,” he said. “Does it really work to ensure that your produce is clean?”

As Subash learned, while intended to kill unwanted pests, the chemicals can also be carcinogenic to humans, cause endocrine or immune system problems, trigger skin reactions and more, 

according to the Environmental Protection Agency

. Some are associated with diseases like Alzheimer’s and Parkinson’s. He didn’t, however, find a device for folks to check if there was pesticide residue on their food, so he decided to fill that gap. 

Subash said he discovered his interest in science in first grade and wanted to apply for the Challenge but almost missed his shot. Students have to be in fifth through eighth grade at the time of their application. 

“I had skipped fifth grade, so I couldn’t enter that year. Sixth grade, my family was in India for a good majority of that time, so I wasn’t able to get my project set up that year. Seventh grade, I did enter, but it didn’t work out,” Subash recalled. “So eighth grade, this is, this was my last year to apply. So I wanted to make it worth it, because this has been somewhat of a dream of mine to make it here.” 

Subash competed against nine other finalists over the last four months with support from a 3M mentor. On Tuesday night he found out his hard work paid off. 

While Subash, who turned 14 Thursday, isn’t totally certain what his future will look like, he does plan to use some of his prize money for higher education. 

“One thing I know is that I love physics… And one of the biggest things I want to do is I want to work on devices that will impact everyday people, that will impact everyone’s lives for the better,” Subash said. “That’s one of my that’s one of my goals in life, to [make] a positive mark on the world.” 

Learn more about Subash and the other Challenge finalists at 

Gracie  Stockton

Author

Cathy Wurzer

Host

Fourteen-year-old Sirish Subash — a ninth-grader from Snellville, Ga. — was crowned the winner of the 2024 3M Young Scientist Challenge contest in St. Paul this week. He picked up a cash prize of $25,000 and the lesson that moms are always right. 


Winner of 3M Young Scientist Challenge invents AI pesticide detector for produce

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