As many of my readers might know the Emerald Ash Borer (Agrilus planipennis) is an introduced insect pest from Asia that feeds on and kills ash trees. The borers attack trees by laying eggs on the bark. The serpentine feeding galleries of the larvae inside the bark disrupt the flow of nutrients and water and starve the tree. All species and sizes of ash trees (genus Fraxinus) are susceptible, except for the so called mountain ash which is actually not a true ash but belongs to the genus Sorbus. If a tree has become infested, mortality will result usually within 2-3 years.
In North America, the beetle was initially discovered in Michigan and southwest Ontario in 2002. Since then this insect pest from Asia that has killed millions of trees throughout the United States and Canada and has caused billions of dollars of damage. Fortunately, its damage has been limited to ash trees - or so we thought.
There is a new publication that provides evidence that the Emerald Ash Borer can also attack different species:
I report here evidence that emerald ash borer can attack and complete development in white fringetree, Chionanthus virginicus L., a species native to the southeastern United States that is also planted ornamentally. Four of 20 mature ornamental white fringetrees examined in the Dayton, Ohio area showed external symptoms of emerald ash borer attack, including the presence of adult exit holes, canopy dieback, and bark splitting and other deformities. Removal of bark from one of these trees yielded evidence of at least three generations of usage by emerald ash borer larvae, several actively feeding live larvae, and a dead adult confirmed as emerald ash borer.
White fringetree, a relative of ash, is a deciduous shrub or small tree that can grow up to 10 m tall. It has white flowers and a purple, olive-like fruit, and is growing in popularity as an ornamental. It is known for its relative lack of pest and disease problems, and until now has never been reported as a host to wood borers.
Now this is indeed bad news which of course needs to be confirmed further and DNA Barcoding should play a big role in more widespread survey and monitoring programs. It is paramount to be able to identify all life stages of the animal to confirm that we are looking at a true infestation. This new observation might not raise big concerns today as the vast majority of infested trees are still ash trees. However, what will happen once the Emerald Ash Borer is done with those?