- Millions of tiny wasps that are natural parasites for the emerald ash borer have been released into wooded areas in 24 states of the US to try and peg back the tree-killing insect’s advances.
- The US Department of Agriculture has researched and approved for release four species of parasitic wasps that naturally target the larval and egg stages of the ash borer, which has killed an estimated 38m ash trees in urban and residential areas.
- The estimated cost of treating, removing and replacing the lost trees is $25bn, according to a report written by USDA and US Forest Service entomologists.
- The tiniest of the wasps looks like a pepper flake on a white surface.
- These wasps lay eggs inside ash borer eggs, preventing them from hatching. Three other wasps, one the size of a gnat, lay eggs inside ash borer larvae, halting development into adult beetles.
- They were identified in China in 2002 and studied for several years before scientists concluded they could be safety released in the United States to fight the ash borer.
- The wasp release program was taking place in 24 of the 26 states where the ash borer has been found
- Ash was the most commonly planted tree species used to replace elm trees decimated from the 1920s through the 1980s throughout North America by Dutch elm disease.