The Emerald Ash Borer (EAB) was accidentally brought to North America from Northeastern Asia along with shipping material (Pugh, et al. 2011). The EAB is thought to have been originally introduced somewhere around Detroit, Michigan, but has spread to Wisconsin, Canada, and very recently in Minnesota.
The EAB inhabits and attacks ash tree forests, and is an invasive species. An invasive species is a foreign species when introduced to an ecosystem, disrupts it by killing off indigenous species. The ash trees EAB kill provide shelter and food for other animals and plants native to the ecosystem. Invasive species usually spread and get out of control if there is no human intervention because ...view middle of the document...
This helps prevent a new introduction point from starting somewhere else, and potentially spreading up to 280 miles away to another, otherwise healthy ash forest. This does not impact the ecosystem, but instead limits human activities.
One way to kill off adult EAB has been tested in a greenhouse, and has shown fairly positive results to control the pests. Beauveria bassiana strain GHA, a type of bacteria was sprayed on logs containing EAB larvae. When emerging from the logs as adults, the EAB come into contact with these bacteria, and makes them susceptible to a fungal infection caused by a fungal band which also sprayed on targeted trees, and kills them. This method was does not kill all of the EAB emerging from a sprayed log, but decreases the life span and ability to reproduce of some. The B. bassiana strain GHA method has little to no impact on the ecosystem because the bacteria have to be sprayed on in planned locations, and cannot live long because it is not their natural environment. This in long term effectively controls the EAB population (Houping, Baur 2007).
There is also a method of EAB which is currently being used in Minnesota, but on urban Emerald Ash Borer populations. Some cities have begun introducing stingless wasps to combat the EAB. These wasps are meant to act as a predator to adult EAB. The goal for the stingless wasp introduction to urban areas is for them to wipe out he EAB population, and then themselves eventually die out because of a lack of a food source. Since these wasps cannot sting, they are not a threat to people in the area.
In EAB populations in Asia, little was known about natural predators prior to North American outbreaks. Since then research has shown that EAB larvae are usually attacked by different kinds of parasitoids while inside the ash logs. Parasitoids are parasites which spend most of their lives connected to or inside of its host. Two species of parasitoids are known to affect native EAB. One is Spathius wasps, the other is Tetrastichus. Multiple spathius wasp larvae attach to EAB larvae and kill it while still inside the log. The same thing happens with Tetrastichus larvae, but some infected EAB live to become adults outside of the ash tree, but then fall victim to the parasitoid soon afterwards (Houping, et al. 2003).