In October 2014, researchers at Wright State University discovered that an invasive insect called the emerald ash borer (EAB) was attacking white fringetrees (Chionanthus virginicus
) in addition to ash trees. This was big news at the time. The EAB had already killed tens of
millions of ash trees, and the fact that it could harm another species
made it even more devastating.
Now the same researchers have found that the EAB can also
successfully complete development on olive trees. Professor Don
Cipollini has found that the invasive green beetle can feed and
successfully develop into adulthood on stems of the Manzanilla olive
tree, a Spanish variety that yields green table olives and is grown
widely around the world.
“We are showing in this experiment that emerald ash borer indeed can
complete development on olive,” said Cipollini. “It would add a
potential pest to the olive cultivation industry. If we see this
happening in nature, it could be a huge deal.”
Native to Asia, emerald ash borer was first found in the United States
near Detroit in 2002. It is believed to have been in ash wood used to
stabilize crates during shipping and may have arrived without notice a
decade earlier. It is estimated that the borer will have caused $10
billion (AU$13.14 billion) in economic damage by 2019.
The borers attack trees by laying their 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.
Cipollini acquired a stem of the Manzanilla olive tree from
collaborators in California and inoculated it with emerald ash borer
eggs. Eggs were placed on the stem in February, and the larvae were
allowed to feed on it for about two months. Beginning in April,
Cipollini and Donnie Peterson, an environmental sciences Ph.D. student
from Black River Falls, Wisconsin, exposed them to cooler temperatures
for two months to simulate winter in order to facilitate their