Hundreds of U.S. residents have received unsolicited packages of seeds, mostly originating from China, among them is Mike Wilson, content director for Farm Futures.

Wilson, who lives in California, got the seeds in the mail this spring.

"I couldn't figure out why. I thought it was a mistake by Amazon," he said. "I started looking for a link to an order for seeds and found some bad reviews from people who got seed they didn't know would come from China. I asked my sister, who is a master gardener, about them and she had no idea so I just threw them away."

Don't throw them away

USDA urges anyone who receives an unsolicited package of seeds to avoid tossing them in the trash and to instead immediately contact their state plant regulatory official or APHIS state plant health director. Retain the seeds and packaging until you hear back from the regulatory agencies and avoid planting the seeds.

Multiple states report seed shipments

USDA and agriculture officials in multiple states have issued warnings about the unsolicited shipments of foreign seeds. Seed packages have been received in at least 18 states. In all cases, the instructions are similar, with officials asking residents not to plant or trash the seeds and to instead call agricultural authorities.

Related:Did you get mystery seeds in the mail?

Kentucky Agriculture Commissioner Ryan Quarles stressed to CBS News that the seeds should not be planted.

"At this point in time, we don't have enough information to know if this is a hoax, a prank, an internet scam or an act of agricultural bio-terrorism," he said. "Unsolicited seeds could be invasive and introduce unknown diseases to local plants, harm livestock or threaten our environment."

USDA says it doesn't have any evidence indicating this is something other than a "brushing scam," where people receive unsolicited items from a seller who then posts false customer reviews to boost sales.

Fresno County (California) Agricultural Commissioner Melissa Cregan told Western Farm Press this illustrates how easy it is to send items to people without regard to human or agricultural safety. Cregan's office employs dog handler teams to regularly scout parcel shipments for plant materials that could be the subject of state or federal quarantines in order to protect California's multi-billion-dollar agricultural industry.

In Minnesota, the state agriculture department reported it had received more than 150 reports of unsolicited packages of seeds appearing to come from China as of Tuesday morning, July 28, according to Allen Sommerfeld, senior communications officer.

Related:3 tips from USDA on suspicious seed packets

MDA officials have asked residents to report if they received seed packages. Those who have are requested to send them to MDA.

“Once in our possession, we have been asked to ship the packages to the USDA for identification and destruction,” Sommerfeld says.

People reporting seed packages are located all over the state, he adds.

MDA asks residents who have received seeds to contact the state’s Arrest the Pest line at 1-888-545-6684 or [email protected] and provide their name, contact information and the date the package was received.

Updates appear on MDA’s Facebook page at https://www.facebook.com/mnagriculture/

In Kansas, Department of Agriculture Public Information Officer Heather Lansdowne said the department has fielded “hundreds” of calls and emails, both from people concerned about receiving the seed and from other farmers, the general public and the media concerned about what is going on.

She said the department is urging any producers who receive a package of seed to notify the department and to hang onto the seed while the department decides how to proceed.

“If you receive a package of this type, please do not plant these seeds. If they are in sealed packaging don't open the sealed package. Instead, please contact KDA’s plant protection and weed control program at 785-564-6698, via email at [email protected], or at the complaint reporting portion of the KDA website: report a seed complaint.

She also warned recipients of the seed should not throw them away.

“Unsolicited seeds could be invasive species, could introduce diseases to local plants, or could be harmful to livestock,” she said.

She said she doesn’t know how many producers have received the seed, but it is “a significant number.”

The seeds received in Kansas are in packaging that has no source information. Some have been labeled “jewelry.” Inside is a plastic zipper baggy of seed and material with print that appears to be Chinese.

Twitter takes

Social media users have added their take on the situation.