A senior official with the International Seed Testing Association (ISTA), which certifies agricultural products, warned this weekend that packages of unlabeled seeds appearing to come from China could represent “seed terrorism.”

Individuals have reported packages with Chinese writing on them arriving to their homes in every American state, and Taiwan as of Monday. Authorities have not yet identified what the seeds are or how the senders chose their destinations. None of the recipients said they ordered seeds online or anything that could easily be mistaken for seeds. The Chinese Communist Party has denied any ties to the packages.

American agricultural officials have expressed concern that the seeds could be of invasive species that could cause significant environmental damage if planted in U.S. soil and warned anyone receiving the packages to immediately contact local authorities.

In the first similar statement from international officials, K. Keshavulu, a vice president of the ISTA, warned this weekend that those outside the United States should also exercise caution if receiving seed packages. As Keshavulu is also the head of the Telangana State Seed and Organic Certification Authority (TSSOCA) in India, mostly Indian media outlets carried his remarks.

“Following the unwanted/unsolicited delivery of such suspicious seed packets for the past one week, the U.S. Department of Agriculture (USDA) has cautioned people, particularly those engaged in farming, against opening such suspicious seed packets, sowing them in farms or backyards or disposing in the garbage and urged them to give information to the officials,” Keshavulu said in a statement Friday. The official speculated the seeds could be a part of either a “brushing scam and seed terrorism.”

A “brushing scam” is a fraudulent way to boost the reputation of a product sold online. Those selling the product write a fake positive review for it under the name of someone who then receives a real, unsolicited package, but not necessarily containing the product reviewed. “Since the name on the review belongs to someone who did receive the product, it’s considered a verified purchase,” Forbes explained.

“These unsolicited seed packets may spread crop diseases and the poisonous seeds may damage the agriculture and allied sectors and also pose health and environmental problems,” Keshavulu reportedly warned. “In the wake of unsolicited packages of seeds creating panic in some countries, people, farmers, seed agencies and associations, the agriculture department, farmers and other agencies should be on high alert. All of them should take precautionary measures.”

The seeds could be carrying pestilent species or simply be members of an invasive species themselves which, when planted, take over the ground around them and kill off native fauna.

While authorities have not documented any known cases of Indian recipients being targeted with unlabeled seeds, India is currently embroiled in an ongoing economic and diplomatic rivalry with China that erupted when Chinese troops illegally pitched tents on the Indian side of their mutual border in the Himalayas, triggering a bloody brawl believed to have killed up to 50 troops. The incident occurred in June and both sides have attempted to engage in diplomacy to prevent a repeat of the event since then, but New Delhi has responded by banning dozens of Chinese mobile applications from use in the country and embracing a grassroots “boycott China” movement.

Indian Foreign Minister Subrahmanyam Jaishankar told the Times of India in remarks published Sunday that both sides are attempting to find a peaceful resolution, but “reaching an equilibrium with China is not going to be easy and India must stand its ground.”

American officials have expressed alarm at the Chinese mystery seeds.

“This could be a very serious matter,” Texas Agriculture Commissioner Sid Miller told Breitbart Texas. “We don’t know what we don’t know, and frankly, I am getting tired of surprises from China.”

“We don’t know what they are, and we cannot risk any harm whatsoever to agricultural production in the United States,” Kentucky Agriculture Commissioner Ryan Quarles said last week. “We have the safest, most abundant food supply in the world and we need to keep it that way.”

“[We are] aware that people across the country have received unsolicited packages of seed from China in recent days,” the USDA said in an official statement. “At this time, we don’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.”

Taiwanese officials issued similar warnings late last week after residents in the country began reporting similar seed parcel arrivals. China illegally claims Taiwan, officially the Republic of China, as a rogue province and regularly threatens to invade it.

The Chinese Foreign Ministry claimed that the postage labels on the packages identifying them as coming from China are counterfeit, denying their identified origin.

The packages began arriving as China lost large amounts of crops last month to historic floods, which are affecting 27 provinces and 24 million people. The loss of crops along the Yangtze River, one of the world’s longest at nearly 4,000 miles, has boosted American agricultural sales. America made its largest sale of corn ever to China in July.

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