The US government has unleashed millions of wasps into 24 states, the Guardian reports. But, contrary to the horrifying mental pictures this creates, the release of the wasps is actually a good thing. The emerald ash borer is believed to have invaded North America in the 1990s via wooden shipping crates from Russia, China, and elsewhere. Since then, the beetle has spread across more than two dozen states from Massachusetts to Louisiana, according to Phys.org. In doing so, the ash borer has killed approximately 38 million ash trees. And that's a $25 billion problem. The possible solution: four species of tiny wasps from China.
These wasps—each about the size of a pinhead—are parasites to the ash borer, which has no natural enemies in North America, the Des Moines Register reports. The wasps lay their eggs in ash borer eggs and larva, killing the beetle in the process. But humans have nothing to fear. The stingless wasps are more likely to be mistaken for gnats than anything else. "The word 'wasps' does create alarm, but they are very small—not recognizable by the average person," Iowa Department of Agriculture rep Mike Kintner tells the Register. After extensive testing with other beetle species, experts are also confident the wasps won't threaten any native insects. Still, even with a seemingly perfect weapon, the battle against the ash borer is far from over. “This isn’t going to save anybody’s tree in their yard," entomologist Ben Slager tells the Guardian. "What we’re working to do is to protect the next generation coming up." (This is the most dangerous tree in the US.)