Emerald Ash Borer
Invasive species are nothing new to the world. However, it has accelerated with increases in world trade and travel. Sometimes species are introduced by accident and other times by bad decisions made by humans. Some of them almost sound like plots for science fiction movies. The spread of the Black Death in medieval Europe and the Zika virus in the past year are two examples that span the centuries.
There are other examples that don't impact human health as dramatically, but can have severe consequences to native species and the economy of large regions. Two invasive species being dealt with now in the U.S. are the Asian Carp and the emerald ash borer.
Emerald Ash Borer
This insect is found in the U.S. and Europe and can destroy vast forests of ash trees. In the U.S. alone some 8 billion trees are in danger with a commercial value of $300 billion. It is believed they were accidently introduced into the U.S. in shipping crates. In some areas they have killed 99% of the ash trees. Ash trees and the emerald borer cover such a wide area that spraying pesticides is not practical.
There are several approaches to control. One is a long term project to produce resistant trees. This involves studying the genome of resistant ash trees from Asia where the trees live with the borer and have had time to develop resistance. If these resistant genes could be incorporated into ash seedlings it is hoped that they will develop resistance. However, this will not help the ash forests now in danger.
The second method being used now is to release wasps that are a natural enemy of the ash borer. They kill the borer larvae by laying their eggs in them. This will not save infected trees, but hopefully will slow the spread. Perhaps I read too much science fiction, but this sounds like the start of something with unknown consequences. What effect will the wasps have outside of killing the ash borer? They have done extensive studies on the wasps. They are native to the U.S., are specific to the ash borer and don't harm people. But what is it that we don't know about them?