Scores of Minnesotans are receiving packages of seeds in the mail, but they didn't order them.
The Minnesota Department of Agriculture said it is not sure what the seeds are and requests anybody who gets a package of the unsolicited seeds not to plant them.
"We're uncertain what these seeds may be and why people are receiving these unsolicited packages," said Denise Thiede, the department's seed unit supervisor. "Until we know more, we encourage people to contact us because of the risk they may pose to Minnesota agriculture and our natural landscapes."
Packages of the tiny, dark seeds are believed have come from China and neighboring Kyrgyzstan, according to return addresses on some of the packages.
A notice titled "Planting Introduction" accompanies the seeds. It tells recipients to choose a nutrient-rich soil, "please keep the water enough, too dry or too wet will cause the seed to die," and to maintain the proper temperature "to allow plants to grow in a comfortable environment."
The instructions also tell customers who have questions about the unnamed product to "contact me and please do not rush to leave bad feedback."
Similar packages have turned up at homes in Louisiana, Utah, Texas and Washington, the Agriculture Department said.
Anybody who receives the seeds should not throw them or the packaging away. They should call the department's Arrest the Pest Line at 1-888-545-6684 or send an e-mail with their name, contact information and date the package was received.
Above all, don't plant the seeds, Thiede said.
The department is working with the U.S. Department of Agriculture to identify and destroy the seeds.