EAB confirmed in Grundy County

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For Immediate Release: Wednesday, Sept. 12, 2018


New infestation of invasive pest discovered in Dike

DES MOINES – The emerald ash borer (EAB), a destructive insect that attacks and kills ash trees, has been detected for the first time in Grundy County. There are now 65 counties in Iowa with confirmed infestations.

Insect samples were collected from a city-owned tree in Dike after an Iowa Department of Agriculture & Land Stewardship (IDALS) worker noticed ash trees showing the signs of a tree under attack. The collected samples were positively identified as EAB by a federal identifier.    

The adult emerald ash borer is a metallic green insect measuring about one-half inch long. The female beetles lay eggs on the bark of ash trees. Following egg hatch the larvae bore into the bark to the fluid-conducting vessels underneath. The larvae feed and develop, cutting the flow of nutrients and, eventually killing the tree. EAB is native to Asia.

The beetle can fly only short distances. There is also the ever-present risk of spreading EAB and other tree-killing pests through human transport of firewood. Use locally-sourced firewood when burning it at home and when traveling, burn firewood where you buy it.

EAB-infested ash trees can include sparse foliage or thinning of the canopy, excessive sprouting of epicormic shoots from the trunk or main branches, increased woodpecker activity, serpentine (“S”-shaped)  galleries under the bark, vertical bark splitting, and 1/8 inch D-shaped emergence holes.

At this calendar date, the window for all preventive treatments has closed. If a landowner is interested in protecting a valuable and healthy ash tree within 15 miles of a known infestation, he or she should have landscape and tree service companies bid on work, review the bids this winter, and treat beginning spring 2019 (early April to mid-May). More details pertaining to treatment are available in Iowa State University Extension and Outreach publication PM2084: https://store.extension.iastate.edu/product/13114.To find a certified applicator in your area, download PM3074 and follow the steps: https://store.extension.iastate.edu/product/Finding-a-Certified-Pesticide-Applicator-for-Emerald-Ash-Borer-Treatment.

The State of Iowa continues to track the movement of EAB on a county-by-county basis. To report a suspected infestation in a new location, contact one of the following:

·         Iowa Department of Agriculture & Land Stewardship, State Entomologist Office: 515-725-1470

·         Iowa Department of Natural Resources: 515-725-8453

·         Iowa State University Extension and Outreach, Entomology: 515-294-1101

To learn more about EAB and to view known locations in Iowa, please visit http://www.iowatreepests.com.

For more information contact any of the following members of the Iowa EAB Team:

·         Mike Kintner, IDALS EAB coordinator, 515-745-2877, Mike.Kintner@IowaAgriculture.gov

·         Robin Pruisner, IDALS state entomologist, 515-725-1470, Robin.Pruisner@IowaAgriculture.gov

·         Jeff Goerndt, DNR state forester, 515-725-8452, Jeff.Goerndt@dnr.iowa.gov

·         Mark Shour, ISU Extension and Outreach entomologist, 515-294-5963, mshour@iastate.edu

·         Tivon Feeley, DNR forest health program leader, 515-725-8453, Tivon.feeley@dnr.iowa.gov

·         Donald Lewis, ISU Extension and Outreach entomologist, 515-294-1101, drlewis@iastate.edu

·         Emma Hanigan, DNR urban forestry coordinator, 515-249-1732, Emma.Hanigan@dnr.iowa.gov

·         Laura Iles, ISU Extension and Outreach entomologist, ISU Plant and Insect Diagnostic Clinic, 515-294-0581, ljesse@iastate.edu

·         Jeff Iles, ISU Extension and Outreach horticulturist, 515-294-3718, iles@iastate.edu

EAB map


Frequently Asked Questions and Answers on Emerald Ash Borer (EAB)

1.   What is the emerald ash borer? It is a very small, shiny green beetle inch long x ⅛ inch wide; about the size of Mr. Lincolns image on a penny).

2.      What does EAB eat? Hosts are species (and cultivars) of ash 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 its 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 United States 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 2-4 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- 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: https://store.extension.iastate.edu/ItemDetail.aspx?ProductID=1482 and http://www.extension.iastate.edu/forestry/iowa_trees/tree_id.html

7.   How do I know if my ash tree is infested?  Look for the following symptoms: https://store.extension.iastate.edu/Product/EAB-or-Native-Borer  and https://store.extension.iastate.edu/Product/Common-Problems-of-Ash-Trees

a.       Canopy 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, whcan help me determine if my tree is infested? Contact one of the following if you suspect EAB in your tree:

a.       Iowa Dept. of Agriculture & Land Stewardship, State Entomologist Office: 515-725-1470

b.      Iowa Department of Natural Resources 515-725-8453

c.       Iowa State University Extension and Outreach, Entomology: 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 treatment of a healthy ash tree during the growing season (see #10 below). If you are not in a known infested area, treatment may be premature.

10.   Ash Borer Management Options:  

a.       There are two management publications available from Iowa State University Extension

1)      English:  https://store.extension.iastate.edu/product/13114

2)      Spanish:  https://store.extension.iastate.edu/product/14762

b.      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.

c.       Most of the systemic insecticide treatments (i.e., imidacloprid and dinotefuran) must be done each year for the life of the tree. Two active ingredients will last for 2 years in a light EAB infestation: emamectin benzoate and azadirachtin. In heavy EAB infestations, only emamectin benzoate is effective for 2 years; azadirachtin must be injected every year.

d.      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.

e.       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.

f.       Ash trees within 15 miles of a confirmed EAB site are at risk of EAB attack. Preventive treatments are suggested within this risk zone, but may be premature outside this area.

Continued monitoring of ash trees outside the risk zone for EAB symptoms is suggested.

g.       Systemic insecticides require time, good soil moisture, and active tree growth for distribution in the ash tree. Most soil-applied products (soil drench, granular, soil injection) must be applied in early spring (mid-April to mid-May) to be effective. Basal trunk sprays [most effective for trees <23”dbh] using dinotefuran can be applied from mid-May through mid-June. Trunk injections can generally be made during full canopy (April through August). Good soil moisture is critical for the effectiveness of any preventive treatment.

h.     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.

i.        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. For assistance in making a list of prospective certified applicators in your county/area, go to: https://store.extension.iastate.edu/Product/Finding-a-Certified-Pesticide-Applicator-for-Emerald-Ash-Borer-Treatment  

j.        There is a per acre use limitation for soil treatments and basal bark treatments; consult the product label when planning applications. There is no per acre use limitation for trunk injections.

k.      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 nontarget 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 for most preventive applications 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 sixty-five Iowa counties. Counties considered infested:

1)      Adair – Bridgewater (Mormon Trail Co. Park), Lake Orient Recreational Area (2016), Greenfield Lake (2018)

2)      Adams – Rural area north of Cromwell (2016)

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

4)      Appanoose – Moravia (2014)

5)      Benton – Belle Plaine (2017)

6)      Black Hawk–Waterloo (2014), Deerwood Park (2017)

7)      Boone Boone (2014), Ledges State Park (2017)

8)      Bremer–Waverly (2014)

9)      Buchanan – Winthrop (2018)

10)  Buena Vista – Alta (2017)

11)  Butler – Clarksville (2017)

12)  Carroll – Rural area west of Carroll (2018)

13)  Cedar – Mechanicsville (2013)

14)  Clarke – Osceola (2016)

15)  Clayton – Marquette, Monona (2017)

16)  Clinton Clinton (2015)

17)  Crawford – Denison (2018)

18)  Dallas Waukee (2015)

19)  Davis – Rural area north of Bloomfield (2015)

20)  Decatur – Rural area north of Grand River (2017)

21)  Delaware – Edgewood (2018)

22)  Des Moines Burlington (2013)

23)  Dubuque – Dubuque (2015), Dyersville (2017)

24)  Fayette – Oelwein (2017)

25)  Floyd – Charles City (2017)

26)  Greene – east of Grand Junction (2017)

27)  Grundy – Dike (2018)

28)  Hamilton – Rural area near Randall (2018)

29)  Hardin – Eldora (2018)

30)  Harrison – Logan, Missouri Valley (2016)

31)  Henry – Mt. Pleasant (2014), Geode State Park (2017)

32)  Howard – Cresco (2017)

33)  Iowa – Lake Iowa Park (2016), north of Middle Amana (2017)

34)  Jackson – Bellevue (2017)

35)  Jasper Newton (2014), Rock Creek State Park (2017)

36)  Jefferson – Fairfield (2013)

37)  Johnson – Coralville, Iowa City (2016), south of Oxford (2017)

38)  Keokuk – Hedrick (2015)

39)  Lee – Fort Madison (2015)

40)  Linn – Cedar Rapids (2015), Toddville (2016), Lisbon (2017), Marion (2018)

41)  Louisa – Rural area in central part of county (2016)

42)  Lucas – Private woodlot (2014), Chariton (2016)

43)  Madison – Rural site south of Winterset (2017), Winterset (2018)

44)  Mahaska Eddyville (2014); rural area NW of Oskaloosa (2015)

45)  Marion – Maryville  (2014), Marion Co. Park (2017)

46)  Marshall – Rural area N of Le Grand (2018), Marshalltown (2018)

47)  Monroe – Private property (2014), Albia (2017)

48)  Montgomery – Rural area NW of Red Oak (2015); rural area north of Villisca (2016)

49)  Muscatine Muscatine (2014)

50)  Page – Clarinda (2018)

51)  Polk – Urbandale, West Des Moines (2015); Des Moines, Mitchellville, Windsor Heights (2016), Johnston (2018)

52)  Poweshiek – Grinnell (2015), Montezuma (2017)

53)  Ringgold – west of Tingley (2017)

54)  Scott – Davenport (2015), Bettendorf (2016), Scott Co. Park (2017), West Lake Park (2017)

55)  Story Story City (2014), Ames (2018)

56)  Tama – Rural area N of Le Grand (2018)

57)  Taylor – Clearfield (2018)

58)  Union Creston (2013)

59)  Van Buren – Birmingham (2016)

60)  Wapello – Eddyville (2014), Eldon (2017)

61)  Warren – Rural Milo (2017)

62)  Washington – Brighton (2016), Washington (2017)

63)  Wayne – north of Corydon (2017)

64)  West Pottawattamie – Council Bluffs (2018)

65)  Winneshiek – Decorah (2016)

13.  Now that EAB has come to Iowa, is there some plan to manage/contain this pest?   A detailed plan has been developed by Iowa’s collaborative agencies. The EAB Response Plan and other current Iowa information about EAB are given athttp://www.extension.iastate.edu/psep/EmeraldAshBorer.html

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? We request that you dispose or use the wood within your county.

17.  Can I use the mulch produced by chipping an EAB infested tree for landscaping? If the chip size is 1 inch x 1 inch or smaller (in two dimensions), recent research has shown that EAB does not survive and the chips can be used without concern. If the chip size is larger, however, it is best to bury or burn these chips (according to local ordinance) as soon as practical to prevent spreading EAB into new areas.

18.  Can I use the wood from an EAB infested ash as firewood? Yes, with one qualification. Once the ash tree is cut into pieces, the pieces can be used as firewood on your property. Please do not take infested firewood with you on camping trips, tailgating, hunting, or other places because you will spread EAB.

19.  What can my ash tree be used for, besides firewood? Depending on the straightness of the trunk and main branches, ash killed by EAB can be processed for lumber or can be debarked and used for outdoor furniture or landscaping. Pieces of scrap wood with the bark still attached should be burned, buried, or chipped.

20.  What general recommendations are available to communities? The Iowa Department of Natural Resources has worked with several communities to deal with EAB infestations. Contact Tivon Feeley (515-725-8453) or Emma Hanigan (515-249-1732) for more information.

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

a.       National: www.emeraldashborer.info

b.      ISU Extension & Outreach: http://www.extension.iastate.edu/psep/EmeraldAshBorer.html

c.       IDALS: www.IowaTreePests.com

d.      IDNR: www.iowadnr.gov/Environment/Forestry/ForestHealth/EmeraldAshBorer.aspx

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

·         Grundy County 319-824-6979

If you live in another Iowa county and would like to contact your Extension & Outreach office, visit http://www.extension.iastate.edu/content/county-offices and click on your county; the phone number is in the blue box in the upper right corner of a county’s web page. 


For more information, contact Dustin Vande Hoef, (515) 281-3375 or (515) 326-1616 (cell) or Dustin.VandeHoef@IowaAgriculture.gov