Madison County now is nearly surrounded by the emerald ash borer (EAB), a destructive pest that feeds on ash trees, and has now spread to 39 counties, with a documented discovery recently in neighboring Clarke County in Osceola.
The Osceola discovery came after an Iowa EAB team member observed symptoms of an EAB infestation in a city owned tree. Further examination of the tree by peeling bark led to the collection of a larva that was confirmed positive by national identifiers.
First EAB outbreak in 2010
The first discovery of the emerald ash borer in Iowa came back in 2010, when the pest was discovered and documented in four locations in Alamakee County, including New Albin, Lansing, Black Hawk Point and Plough Slough.
There were no findings in either 2011 or 2012, but in 2013, the EAB showed up in four more Iowa counties, including neighboring Union County, in Creston. That discovery put southwest Madison County land owners on alert that the ash borer might be on the wing to that area of Madison County. The Asian beetle was also discovered in Cedar, Des Moines and Jefferson counties in 2013.
In 2014, the ash borer encroached upon more than a dozen Iowa counties. It was verified in two central Iowa locations – in Boone and also in Story City – as well as in Appanoose, Black Hawk, Bremer, Henry, Jasper, Lucas, Mahaska, Marion, Monroe, Muscatine and Wapello counties.
The 2014 Mahaska County discovery came in Eddyville. A year later, however, in 2015, the ash borer was discovered a second time in Mahaska County, in a rural area northwest of Oskaloosa.
Another dozen counties also succumbed to the pest in 2015, with four counties reporting a first finding, only to be found to have spread a year later. That was in Linn, Montgomery, adjacent Polk County, as well as Scott County.
Not only was the ash borer found in Urbandale and West Des Moines in 2015, it also was found in neighboring Dallas County, in Waukee. Those findings put northeast Madison County property owners on alert that the bug was continuing its migration across the area. Earlier this year, more outbreaks of the ash borer came in Des Moines, Windsor Heights and Mitchellville.
In recent months, the ash borer was documented in neighboring Adair County in two locations: near Bridgewater in western Adair County and also at the Lake Orient Recreation Area. The Lake Orient find put southwest Madison County property owners on alert that the borer was expanding its territory. Madison County found itself nearly surrounded by the pest.
Then came the Osceola discovery.
Adair County had been the 38th Iowa county to verify the ash borer infestation. This week, Clarke County became county No. 39, meaning folks in southeast Madison County should now be vigilant of the insect’s insidious march.
In all, discoveries have been made and verified in 14 Iowa counties this year, four for the second time –in Linn, Montgomery,
Scott and Polk counties.
What to look for
Look for the following symptoms:
• Canopy thinning or dying branches in the top of the tree.
• Water sprouts (suckers) halfway up the trunk of a tree
• Feeding notches on edge of leaflets;
• Woodpecker activity/feeding sites. Check for bark flakes on the lawn.
• S-shaped feeding galleries under dead bark;
• D-shaped exit holes.
For more EAB information, check online at:
Reverse chronology of Iowa EAB discoveries, by county
2016 (14) [2-2nd time in 4 counties]: Adair, Bridgewater (Mormon Trail Co. Park), Lake Orient Recreational Area; Adams, Rural area north of Cromwell; Clarke, Osceola; Harrison, Logan, Missouri Valley; Iowa, Lake Iowa Park; Johnson, Iowa City; 2-Linn, Toddville; Louisa, central Louisa County; 2-Montgomery, rural area north of Villisca; 2-Polk, Des Moines, Mitchellville, Windsor Heights; 2-Scott, Bettendorf; Van Buren, Birmingham; Washington, Brighton; Winneshiek, Decorah.
2015 (12): Clinton: Clinton; Dallas: Waukee; Davis: north of Bloomfield; Dubuque: Dubuque; Keokuk: Hedrick; Lee: Fort Madison; 1-Linn: Cedar Rapids; 2-Mahaska: rural area NW of Oskaloosa; 1-Montgomery: rural area NW of Red Oak; 1-Polk: Urbandale, West Des Moines; Poweshiek: Grinnell; 1-Scott: Davenport.
2014 (13): Appanoose, Moravia; Black Hawk, Waterloo; Boone, Boone; Bremer, Waverly; Henry, Mt. Pleasant; Jasper, Newton; Lucas, private woodlot; 1-Mahaska, Eddyville; Marion, Maryville; Monroe, private property; Muscatine, Muscatine; Story, Story City; Wapello, Eddyville
2013: Union: Creston; Cedar: Mechanicsville; Des Moines: Burlington; Jefferson: Fairfield.
2010: Allamakee, New Albin, Lansing, Black Hawk Point, Plough Slough.