To stop the emerald ash borer from killing trees in Minnesota, the state brought in a natural predator two years ago…and the tactic seems to be working.
Experts with the Minnesota Department of Agriculture have found proof that stingless wasps are breeding, and spreading through the area. The wasps attack the eggs and larva of the ash borer. They were released in Houston and Winona Counties in 2011, and this fall, the M-D-A found wasp larvae on trees that had been sampled for the ash borer. That wasp is the ash borer’s only known natural enemy.