Moss balls and mystery seeds

Episode 18, June 16, 2021

Moss balls and mystery seeds

In Moss balls and mystery seeds, we dive deep into two news stories that involved some unexpected international hitchhikers.

In the summer of 2020, individuals all over the United States started receiving random packages of unsolicited and unidentified seeds. Why was this happening? Were these seeds noxious or invasive? While thousands of packages of seeds piled up for investigation at his U.S. Department of Agriculture office, Christopher Deegan tried to answer these questions.

Less than a year later in the spring of 2021, pet stores around the country discovered that the moss balls on their shelves carried a notorious aquatic hitchhiker. Amy Kretlow remembers visiting her local Sheboygan, Wisconsin, pet store only to find zebra mussels on the store’s moss ball stock. Amy spent months helping to deal with this first-of-its-kind international crisis.

Unsolicited seeds came in small international mail envelopes. Inside, they contained a tiny Ziplock bag of seeds. Sometimes the label read “squash,” “corn” or “tomato.” Even stranger, sometimes the envelopes would be labeled “earrings” or “jewelry.”

Introduced zebra mussels feed by voraciously filtering tiny plants and algae out of the water. In some conditions, zebra and quagga mussels can now filter all of Lake Michigan in less than two weeks, leaving other lake dwellers, like larval fish, scrambling for food. Photo: U.S. Geological Survey.


Smiling woman standing in front of a lake.

Bonnie Willison | Host

Video Producer

What I do at Sea Grant

As the videographer and digital storyteller, Bonnie uses her video and animation skills to showcase the stories of Wisconsin Sea Grant.

Sydney Widell | Host

Student podcast producer

What I do at Sea Grant

Sydney brings her background in geography and journalism to Wisconsin Sea Grant, where she is the co-producer and co-host of Introduced.