Tree-Killing Insect Confirmed In Five More Counties In Iowa

Tree-Killing Insect Confirmed In Five More Counties In Iowa

With this latest discovery, Emerald Ash Borer has now been positively identified in 18 counties in the state.

Emerald Ash Borer has been positively identified in Appanoose, Lucas, Mahaska, Marion and Monroe counties in southern Iowa. The Iowa Department of Agriculture & Land Stewardship made the announcement December 15, bringing the total to 18 counties with confirmed infestations in the state. EAB kills all ash tree species and is considered to be one of the most destructive tree pests ever seen in North America.

BAD BUG: On December 15 state ag officials announced Emerald Ash Borer has been discovered in Appanoose, Lucas, Mahaska, Marion and Monroe Counties in southern Iowa. This brings the total to 18 counties with confirmed infestations of the tree-killing insect pest.

The discovery of this latest series of infestations started when a forestry contractor found many dead ash trees with heavy woodpecker flecking while completing a timber stand improvement project on privately-owned woodland on the far eastern edge of Lucas County. The infestation appears to have been in place for several years. The larvae were located only 3/8th of a mile from Monroe County. State EAB team members continued to examine trees in the area and additional larvae were found in ash trees on public property in Monroe County, near the Lucas site.

In Marion County EAB larvae were found in a heavily-flecked ash tree on state property on the edge of Marysville. In Appanoose County larvae were found in a tree along train tracks in Moravia. And, in Mahaska County larvae were collected from a tree on private property on the north side of Eddyville.

Statewide quarantine was issued in early 2014 and is still in effect
A statewide quarantine, issued on Feb. 4, 2014, remains in place. It restricts the movement of hardwood firewood, ash logs, wood chips and ash tree nursery stock out of Iowa into non-quarantined areas of other states.

What should you watch for, as signs of this pest? "Woodpecker-flecked ash trees are a great calling-card when investigating an insect infestation. The damage symptoms on ash trees are very visible during winter months. Woodpeckers feed on more than Emerald Ash Borer, but when we find woodpeckers focusing on ash trees in an area, it's a red flag that begs for further investigation," says state entomologist Robin Pruisner, with the Iowa Department of Agriculture & Land Stewardship.


"We urge Iowans to be vigilant, and report suspicious symptoms in counties that are not yet known to be infested. Report the suspicious symptoms to a member of the Iowa EAB Team. We also continue to urge citizens to keep firewood local, don't pack a pest to a new area," says Mike Kintner, coordinator of the EAB and Gypsy Moth monitoring and management program for IDALS.  

EAB team can help landowners identify and diagnose this pest
The Iowa EAB Team provides EAB diagnostic assistance to landowners and includes officials from the Iowa Department of Agriculture & Land Stewardship, Iowa State University Extension and Outreach, Iowa Department of Natural Resources or DNR, USDA's Animal Plant Health Inspection Service and the USDA Forest Service.

The Iowa EAB Team strongly cautions Iowans not to transport firewood across county or state lines, since movement of firewood throughout Iowa or to other states poses the greatest threat to quickly spread EAB and other plant pests. Most EAB infestations in the United States have been started by people unknowingly moving infested firewood, nursery plants or sawmill logs. The adult beetle also can fly short distances, approximately 2 to 5 miles.

Insecticide can be used on ash trees for prevention of EAB infestation. The next window for preventive treatment measures (trunk injection, soil injection, soil drench, or basal trunk sprays) will open in early spring 2015 (from mid-April to mid-May). If a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation, they should use the winter months to have landscape and tree service companies bid on the work and these bids can be reviewed before next spring.

Contact a member of Iowa EAB team if you see signs of this pest
To have suspicious looking trees checked in counties not currently known to be infested with EAB, you should contact a member of the Iowa EAB Team, advises Pruisner. The State of Iowa will continue to track movement of EAB on a county-by-county basis, she says. Before a county can be officially recognized as infested, proof of a reproducing population is needed and an emerald ash borer must be collected and verified by USDA entomologists.


To learn more about EAB and other pests threatening Iowa's tree population, visit Contact any of the following members of the Iowa EAB Team for further information:

Robin Pruisner, IDALS State Entomologist, 515-725-1470, [email protected]

Paul Tauke, DNR State Forester, 515-725-8450, [email protected]

Tivon Feeley, DNR Forest Health Coordinator, 515-725-8453, [email protected]

Emma Hanigan, DNR Urban Forest Coordinator, 515-725-8454, [email protected]

Mike Kintner, IDALS EAB Coordinator, 515-745-2877, [email protected]

Jesse Randall, ISU Extension Forester, 515-294-1168, [email protected]

Mark Shour, ISU Extension Entomologist, 515-294-5963, [email protected]

Laura Jesse, ISU Extension Entomologist, ISU Plant and Insect Diagnostic Clinic, 515-294-0581, [email protected]

Donald Lewis, ISU Extension Entomologist, 515-294-1101, [email protected].

Jeff Iles, ISU Extension Horticulturist, 515-294-3718, [email protected]

Frequently Asked Questions/Answers on Emerald Ash Borer (EAB)
The following questions and answers were prepared by Mark Shour, Laura Jesse and Donald Lewis, Iowa State University Extension entomologists, on December 15, 2014.

1. What is the emerald ash borer? It is a very small, shiny green beetle (½ inch long x ? inch wide; about the size of Mr. Lincoln's image on a penny).

2. What does EAB eat? Hosts are species (and cultivars) of ash trees in the genus Fraxinus. Hosts include green ash (e.g., Marshall Seedless, Patmore and Summit), white ash (e.g., Autumn Purple), black ash, blue ash and pumpkin ash. Manchurian and Chinese ash trees are primary hosts in EAB's homeland [Eurasia]. A new host record of white fringetree (Chionanthus virginicus) was discovered in Ohio; this is not a common plant in Iowa. Mountain ashes (Sorbus species) are NOT hosts.

3. Where is EAB from? This beetle is native to Asia and is found in China and Korea. It also has been reported in Japan, Mongolia, the Russian Far East and Taiwan. EAB arrived in the United States sometime before 2002 in wood packing materials. It has been recorded feeding on F. chinensis and F. mandshurica as a native borer.

4. How did it get to Iowa? Most EAB infestations in the U.S. have been started by people unknowingly moving infested firewood, nursery plants or sawmill logs. The adult beetle also can fly short distances (2 to 5 miles).


5. Should I be concerned about EAB? Yes. It kills ash trees, usually in 2 to 4 years. In the Midwest, millions of ash trees have been killed by EAB since 2002. There are about 3.1 million urban ash trees and an estimated 52 million ash trees in forests in the state of Iowa. Statewide, Iowa averages 16% to 17% ash on city property, though the ash component in tree inventories can reach 87%.

6. How do I know if I have an ash tree in my yard? Two sources to check on tree identification are: and

7. How do I know if my ash tree is infested?  Look for the following symptoms:  and

a) Thinning or dying branches in the top of the tree

b) Water sprouts (suckers) halfway up the trunk

c) Feeding notches on edge of leaflets

d) Woodpecker feeding sites/many bark flakes on lawn

e) S-shaped feeding galleries under dead bark

f)  D-shaped exit holes (1/8 inch diameter)

8. For counties not yet known to be infested with EAB, who can help me determine if my tree is infested? Contact one of the following if you suspect EAB in your tree:

a) State Entomologist Office, IDALS: 515-725-1465

b) Iowa DNR Forestry 515-725-8453 or 515-725-8201

c) ISU Extension and Outreach 515-294-1101

9. Who should be thinking about treating ash trees? If you are a homeowner within 15 miles of a known infested area, you can consider using an insecticide treatment on a healthy ash tree during the growing season (see Question #10 below). If you are not in a known EAB infested area we do not recommend treatment at this time.

10. Ash Borer Management Options Visit the ISU Extension website.

a) Ash trees can be protected with insecticide applied by a commercial pesticide applicator or the homeowner. Trees must be healthy, vigorously growing and valuable to your landscape.

b) Most of the treatments must be done each year for the life of the tree. There is one treatment that lasts for two years (active ingredient is emamectin benzoate).


c) Keep in mind that treatment may not be effective for a given tree due to past injuries, age of the tree, soil moisture, soil compaction, and other site and environmental factors.

d) Preventive treatments are most effective. Infested trees with less than 30% dieback of the crown might be saved for a few years, but the tree's crown will be misshaped as a result of removing the dead branches.

e) Preventive treatments for EAB are NOT recommended until a confirmed EAB site is 15 miles away. Treatment outside this risk zone is not prudent.

f) Systemic insecticides require time and active tree growth for distribution in the ash tree. NOTE: Most products must be applied in early spring to be effective. Products containing emamectin benzoate can be trunk-injected throughout the growing season (until September 1) by a certified commercial pesticide applicator.

g) Soil drench homeowner treatments are effective for ash trees up to 60 inches in

circumference (20 inches diameter), while granular treatments are recommended for trees up to 36 inches in circumference (12 inches diameter). Homeowners can make only one application per year. Trees larger than 60 inches in circumference (20 inch diameter) will need to be treated by a certified commercial pesticide applicator.

h) There are several treatment options available for ash trees when a commercial pesticide applicator makes the application. Always use a certified applicator with experience in treating trees.

i) There is a per acre use limitation for soil treatments and basal bark treatments; consult the product label when planning applications.

j) ISU Extension and Outreach does NOT recommend canopy sprays because of limited effectiveness, the need for specialized equipment, spray drift, and possible adverse effects to non-target organisms.

11.  If I am contacted by a pesticide applicator to treat ash trees for EAB in the fall or winter, what course should I take?  The best time to make a preventive application for EAB is spring; some products can be used throughout the summer and early fall (before leaf color starts to change). If you live within 15 miles of a confirmed EAB infested site, get an estimate for the treatment. It is best to get at least one additional estimate before any work is done. If you live outside the risk zone, thank the applicator for showing interest and keep the company information on file.


12. Where has EAB been found in Iowa? EAB infestations have been confirmed in 18 Iowa counties. Johnson County is not considered infested at this time based on the finding of a single adult beetle; there is no evidence of a reproducing population in this county. Counties considered infested:

a)  Allamakee—New Albin, Lansing, Black Hawk Point, Plough Slough (2010)

b)  Appanoose – Moravia (2014)

c)  Black Hawk–Waterloo (2014)

d)  Boone – Boone (2014)

e)  Bremer–Waverly (2014)

f)   Cedar – Mechanicsville (2013)

g)  Des Moines – Burlington (2013)

h)  Henry – Mt. Pleasant (2014)

i)   Jasper – Newton (2014)

j)   Jefferson – Fairfield (2013)

k)  Lucas – Private woodlot (2014)

l)   Mahaska – Eddyville (2014)

m) Marion – Marysville  (2014)

n)  Monroe – Public property near Lucas Co. find (2014)

o)  Muscatine – Muscatine (2014)

p)  Story – Story City (2014)

q)  Union – Creston (2013)

r)   Wapello – Eddyville (2014)

13. Now that EAB has come to Iowa, is there some plan to manage/contain this pest? Yes, a detailed plan has been developed by collaborative agencies. The EAB Response Plan and other current Iowa information about EAB are available online.

14. What does an EAB quarantine mean? A quarantine by state and U.S. agriculture departments means that hardwood firewood, ash logs, and wood chips cannot be moved out of the area without a permit. Homeowners must not remove their ash tree or firewood from their tree to an area outside the quarantine. Tree removal companies must not haul logs or firewood outside the quarantine area unless inspected and treated as required by the regulations.

15. How many counties in Iowa have been quarantined?  The entire state (99 counties) of Iowa has been quarantined for EAB.

16. What should a homeowner or tree care company do with ash trees cut down in or near the infested area? Dispose or use the wood within the quarantined area.

17.  What general recommendations are available to communities? The Iowa Department of Natural Resources – Forestry Bureau has worked with several communities to deal with EAB infestations. Contact Tivon Feeley (515-281-4915) or Emma Hanigan (515-281-5600) for more information.


18.  Where can I find current information about EAB on the Internet? Sites to gather current information about this exotic pest include:

a) National site

b) ISU Extension & Outreach site

c) IDALS site

d) IDNR site

19. Who is a local contact? Call your county Iowa State University Extension & Outreach office for more information.

Appanoose – [641] 856-3885

Lucas – [641] 774-2016

Mahaska – [641] 673-5841

Marion – [641] 842-2014

Monroe – [641] 932-5612

TAGS: USDA Extension
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