This article was published originally on 2/14/2014
The emerald ash borer (EAB) was positively identified on January 29, 2014, in several city trees in Waterloo, IA, making Black Hawk County the sixth location where this invasive beetle has been found in Iowa. EAB kills all ash tree species and is considered to be one of the most destructive insect tree pests ever seen in North America. Read the news release at the ISU Extension and Outreach website.
Unlike other EAB finds in the state, this infestation was uncovered as the City of Waterloo forestry crew was doing systematic trimming of street trees in northeast Waterloo. The crew had been trained to look for EAB symptoms years earlier, and when they saw suspicious branches, they removed them, bark peeled them, and collected larvae for identification. The USDA APHIS PPQ national identifier confirmed the larvae were EAB.
The city forester, Todd Derifield, and an IDALS entomologist, Todd Voss, visited the neighborhood a few days later and determined the affected area is approximately 10 blocks by 10 blocks; additional survey work will be necessary to see the size of this EAB infestation. Woodpecker flecking and D-shaped exit holes were symptoms used to estimate the initial size of the infestation (see photos below).
Waterloo has 4,364 ash trees on the city right-of-way, parks, and golf courses. The number of private ash trees in the city is not known. Although the City of Waterloo has removed several hundred ash trees in recent years, Derifield estimates the cost of removing and replacing the remaining public trees would be $3 million.
Other known EAB infested counties are Allamakee, Cedar, Des Moines, Jefferson, and Union. The Black Hawk County find is closest to Mechanicsville, IA in Cedar County. The transport of firewood that contained EAB adults or larvae is the likely source of starting the Waterloo infestation.
"Flecking" is one indication of an EAB infestation and is where woodpeckers have picked off the tree bark to get to the larvae below.
Holes made when EAB adults emerge from an infested tree are characteristically "D" shaped and 1/8 inch wide. Photo by Dan Herms.
Initial county EAB detections.