In the 1956 sci-fi classic “Invasion of the Body Snatchers,” alien plant spores fall from space and grow into large seed pods, each one capable of reproducing a duplicate copy of every human on Earth. Today — without the alien doppelgangers — frightened Brazil’s agricultural authorities warn that a similar phenomena could be in progress, after hundreds of suspicious, unsolicited packages containing mysterious seeds were sent to Brazilian homes through the post.
At least 258 samples of seeds have been turned in to authorities in all but two Brazilian states, and the Agriculture and Health Ministries have launched a joint...