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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Emerald Ash Borer Found in Southeast Iowa

This article was published originally on 7/26/2013

On July 16, 2013, a new infestation of emerald ash borer (EAB) was confirmed in Burlington, Iowa.  Like many EAB infestations, this one was discovered by a homeowner worried about the declining condition of an ash tree.  
 
Below is the account of how this EAB infestation was discovered and the numerous steps (following the Iowa EAB Readiness Plan) that lead up to notification of the public and what steps will follow in the coming months and years.
 
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Several pieces of bark that had fallen on a front lawn alerted a citizen of Burlington, Iowa to look up at this landscape trees.  In his 40-foot tall ash tree he saw woodpecker flecking, dying leaves, and dead branches. He called Casey Chadwick, Forester for the City of Burlington, who came out and looked at the tree.  Suspecting something different than the run-of-the mill ash decline (see ISU publication SUL 0002), Casey asked for assistance from the Iowa Department of Natural Resources-Forestry Bureau.   Lisa Louck (District Forester) and Tivon Feeley (Forest Health Leader) investigated the tree and found two characteristic signs of the emerald ash borer: D-shaped emergence holes in the bark and serpentine tunnels underneath the bark.
 
On July 10, 2013, a response team was called in to further examine the tree.  This team consisted of representatives from Iowa Department of Agriculture and Land Stewardship (IDALS), Iowa State University Extension and Outreach, Iowa Department of Natural Resources, and United States Department of Agriculture’s Plant Protection Quarantine (USDA PPQ).   
 
Water-sprouts (suckers, epicormic growth) were noted on a section of the tree just below wilting, yellow leaves and dead branches. Water sprouts are a common symptom of EAB infestation.  Working with the city forester a large branch was removed from the tree so it could be examined more closely.  Serpentine galleries, D-shaped holes, woodpecker feeding sites, and one dead adult beetle (emerald green in color) that had failed to emerge were found.
 
The dead beetle was extracted from the wood and placed in hand sanitizer in a screw-top vial.  The sample was shipped overnight to the USDA PPQ EAB specialist in Michigan.  On July 12, 2013, the report came back that the specimen was positively Agrilus planipennis, the emerald ash borer.  Each new county infestation must be confirmed with a physical sample identified by USDA PPQ.  Once the infestation has been confirmed by the USDA the team works quickly to inform local officials and issue a press release to the public.  
 
The next steps will be:

  • State and federal agencies will work with local officials, homeowners and tree care companies to determine the extent of the EAB infestation in Des Moines County.
  • Determine as best we can the age of this EAB infestation and guess how EAB arrived in Burlington.
  • Quarantines by IDALS and USDA will be issued to restrict movement of infested material out of the area.
  • Further information and programs will be available to help local officials and homeowners as they assess and treat or remove ash trees.
  • Regulators will work with the wood industry in the area to comply with quarantine requirements.

 
Insecticide Treatments
 
It is too late to treat for EAB this year.  Any preventive treatments homeowners choose to use must wait until next spring (April-May 2014).  Treatments should be considered to protect trees within 15 miles of Burlington under the following considerations: 1) is the ash tree growing vigorously?  2) is the tree valuable to the landscape?  3) are you willing to continue treatments (most are each year) for the life of the tree?
 
Smaller residential trees (under 8” diameter) can be treated by homeowners using an insecticide soil drench.  Larger trees need to be treated by a certified commercial pesticide applicator.  Treatment options for EAB are provided in Iowa State University Extension & Outreach publication PM-2084
 
 
Emerald ash borer larva found in Burlington IAEmerald ash borer larva found in Burlington IA
 
Ash tree with crown die-back caused by the emerald ash borer.
Ash tree with crown die-back caused by the emerald ash borer.