Plant Disease Clinic2006 Annual Report

Plant Disease Clinic327 Bessey Hall · Ames, IA 50011 · (515) 294-0581sickplant@iastate.edu · www.plantpath.iastate.edu/pdc

Paula H. Flynn Christine Engelbrecht Diagnostician Diagnostician cengel@iastate.edu

Mark L. Gleason Alison RobertsonExtension Plant Pathologist Extension Plant Pathologistmgleason@iastate.edu alisonr@iastate.edu

Gregory L. Tylka X. B. YangExtension Plant Nematologist Extension Plant Pathologistgltylka@iastate.edu xbyang@iastate.edu

AcknowledgmentsCarla Harris, Extension Plant Pathology secretary, provides support in clinic data entry, client correspondence, and compiling the clinic annual report.

Other members of the Department of Plant Pathology who have contributed to plant problems diagnosis include Gwyn Beattie, Edward Braun, Tom Harrington, John Hill, Leonor Leandro, Sande McNabb, Rich Pope, and Dave Volkers.

Rashelle Matthiesen-Anderson worked as the part-time assistant providing diagnostic support for the Plant Disease Clinic.

Specialists in various departments outside of the Department of Plant Pathology contribute to the diagnosis of plant problems submitted to the Plant Disease Clinic. With their help, we are better able to provide answers to a wide range of questions.

Department of AgronomySteve Barnhart, Roger Elmore, Robert Hartzler, Mike Owen, Palle Pedersen, and John Sawyer

Department of Ecology and Evolution and Organismal BiologyRosanne Healy, Deb Lewis, Steve Mahoney, and Lois Tiffany

Department of EntomologyLaura Jesse, Donald Lewis, Marlin E. Rice, and Mark Shour

Department of HorticultureNick Christians, Paul Domoto, Richard Gladon, Cindy Haynes, Jeff Iles, Richard Jauron, Dave Minner, Gail Nonnecke, Arlen Patrick, James Romer, and Hank Taber

Department of Natural Resource Ecology and ManagementTivon Feeley and Jim Pease

Quince rust on hawthorn

Frost injury on yew

Blossom end rot of tomato

Cedar-apple rust

2006 Clinic Activity Month

SampleCategory January February March April May June July August September October November December Total

Annuals 0 1 4 5 0 3 6 2 0 0 0 0 21Broadleaf Trees 1 3 0 3 64 124 85 101 46 22 2 0 451Coniferous Trees 7 4 9 39 38 47 37 38 18 22 3 1 263Field Crops Forage Crops 0 0 0 1 4 1 0 0 1 0 0 0 7 Row Crops 0 0 0 0 3 31 26 29 12 19 3 1 124 Small Grains 0 1 0 1 0 1 2 0 0 0 0 0 5 Specialty Crops 0 0 0 0 0 3 1 5 4 0 0 1 14Fruit 0 0 0 1 3 26 15 7 9 5 0 1 67Miscellaneous 1 0 1 2 4 11 8 11 8 3 2 2 53Perennials 0 0 3 3 6 10 10 3 1 2 0 0 38Plant Identification 0 0 0 0 3 11 5 8 3 2 0 0 32Potted Plants 3 2 0 1 0 1 1 1 1 3 1 0 14Turfgrass 1 0 1 9 5 20 12 13 1 5 1 0 68Vegetables 0 1 1 2 2 10 22 8 2 3 1 0 52Woody Ornamentals 1 0 0 6 9 17 9 16 10 2 0 1 71

TotalPlantSamples 14 12 19 73 141 316 239 242 116 88 13 7 1280

Telephone Inquiries 27 19 25 50 107 209 175 159 79 74 25 25 974Soil Samples 7 18 32 14 7 13 11 69 30 131 257 63 652E-mail Inquiries 100 103 107 124 247 305 220 222 155 126 48 32 1789

Total 148 152 183 261 502 843 645 692 380 419 343 127 4695

The Clinic MissionThe Plant Disease Clinic provides diagnostic support for county and area extension personnel and the citizens of Iowa. The clinic is housed in the Department of Plant Pathology at Iowa State University and is supported by the Iowa State University Extension Integrated Pest Management Program.

The Plant Disease Clinic responds to requests for plant health information from farmers, growers, and the general public via telephone calls, e-mails, face-to-face encounters, and plant and soil samples submitted for analysis. Responses focus on educating the clients in ecologically sound plant disease management practices. A $10 fee is assessed for the diagnosis of plant samples, and a $15 fee is assessed for analyzing soil samples for soybean cyst nematodes.

An important function of the clinic is to keep growers and gardeners informed on current and potential plant health management issues. Timely news articles and radio interviews help growers and gardeners, and also help county extension personnel anticipate and meet the needs of their clientele.

Paula Flynn, Plant Disease Clinic Diagnostician

Wilting caused by Dutch elm disease

Thank you for the many wonderful years of service you gave to the Iowa State University Plant Disease Clinic. Good luck in your future endeavors; you will be missed by all of Iowa State University and the citizens of Iowa that you have helped with their plant diseases over the past years.

Yellowing of maple due to Verticillium wilt

2006 Plant Disease Clinic activity

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Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

E-mail Inquiries Soil Samples Plant Samples Phone Inquiries

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Long-Term Trendsin Clinic Activity—Plant Samples

Long-Term Trendsin Clinic Activity—SCN Samples

Distribution of Plant Sample Types Clientele Samples

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2000 2001 2002 2003 2004 2005 2006

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Commercial Extension General Public

Mail Walk-in

Broadleaf Trees34%

ConiferousTrees21%Field Crops

12%Perennialsand Annuals5%

Turf5%

Vegetables4%

Fruit5%

WoodyOrnamentals6%

Miscellaneous4%

Plant ID3%

PottedPlants1%

2000 2001 2002 2003 2004 2005 2006N

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200

400

600

800

1000

1200

1400

1600

WASHINGTON11

LOUISA4

TAMA10

MARSHALL12

JOHNSON31

IOWA7

POWESHIEK4

JASPER12

MARION9

MAHASKA7

KEOKUK8

MONROE1

APPANOOSE2

CEDAR14

CLINTON25

SCOTT15

MUSCATINE28

VAN BUREN1

WAPELLO1

DAVIS8

JEFFERSON8

HENRY13

DES MOINES15

LEE19

BENTON6

LINN28

JONES6

JACKSON16

DUBUQUE23

DELAWARE20

BUCHANAN14

BLACK HAWK23

GRUNDY3

BREMER5

BUTLER1

ALLAMAKEE3

WINNESHIEK6

HOWARD4

MITCHELL6

WORTH2

CERRO GORDO42

FRANKLIN4

FLOYD5

CHICKASAW4

CLAYTON0

FAYETTE5

HARDIN10

WRIGHT17

KOSSUTH13

HUMBOLDT2

BOONE35

HAMILTON17

HANCOCK5

WEBSTER27CALHOUN

4

PALO ALTO6

STORY180

WINNEBAGO0

GREENE15

POCAHONTAS0

CARROLL22

EMMET4

SHELBY0

SAC4

CHEROKEE3

DICKINSON9

HARRISON23

IDA6

BUENA VISTA3

OSCEOLA3

CRAWFORD12

WOODBURY8

CLAY7

LYON17

MONONA11

PLYMOUTH4

O'BRIEN6

SIOUX5

TAYLOR5

RINGGOLD6

DECATUR2

WARREN11

POLK144

LUCAS1

WAYNE0

MADISON27

DALLAS10

CLARKE6

ADAMS1

ADAIR10

AUDUBON1

UNION11

MILLS2

GUTHRIE10

MONTGOMERY6

POTTAWATTAMIE19 5

CASS8

FREMONT3

PAGE4

OUT OF STATE17

Number of Plant Samples Received by County

OUT OF STATE3

WASHINGTON11

LOUISA4

TAMA3

MARSHALL0

JOHNSON6

IOWA0

POWESHIEK4

JASPER19

MARION3

MAHASKA4

KEOKUK0

MONROE1

APPANOOSE0

CEDAR3

CLINTON0

SCOTT2

MUSCATINE12

VAN BUREN0

WAPELLO0

DAVIS0

JEFFERSON1

HENRY20

DES MOINES0

LEE7

BENTON12

LINN2

JONES3

JACKSON2

DUBUQUE2

DELAWARE0

BUCHANAN0

BLACK HAWK15

GRUNDY5

BREMER2

BUTLER0

ALLAMAKEE0

WINNESHIEK0

HOWARD0

MITCHELL0

WORTH0

CERRO GORDO16

FRANKLIN0

FLOYD0

CHICKASAW0

CLAYTON0

FAYETTE0

HARDIN3

WRIGHT2

KOSSUTH16

HUMBOLDT9

BOONE35

HAMILTON1

HANCOCK0

WEBSTER9CALHOUN

6

PALO ALTO13

STORY49

WINNEBAGO0

GREENE1

POCAHONTAS7

CARROLL19

EMMET2

SHELBY29

SAC0

CHEROKEE2

DICKINSON4

HARRISON1

IDA0

BUENA VISTA28

OSCEOLA12

CRAWFORD2

WOODBURY0

CLAY75

LYON10

MONONA0

PLYMOUTH0

O'BRIEN44

SIOUX21

TAYLOR0

RINGGOLD0

DECATUR0

WARREN5

POLK0

LUCAS0

WAYNE2

MADISON4

DALLAS0

CLARKE0

ADAMS20

ADAIR16

AUDUBON0

UNION35

MILLS6

GUTHRIE2

MONTGOMERY0

POTTAWATTAMIE1 2

CASS0

FREMONT0

PAGE0

Number of Soil Samples Received by County

2006 Common Infectious Disease ProblemsExamples of diseases diagnosed at the Iowa State University Plant Disease Clinic are listed below according to host. About half of the plant samples received in 2006, especially trees and shrubs, showed symptoms related to adverse site conditions, improper cultural practices, or environmental stresses, rather than infectious disease.

BroadleafTreesash anthracnose, ash rust, Verticillium wiltcatalpa Verticillium wiltcherry black knot, cherry leaf spotcrabapple apple scab, fire blightelm anthracnose, Dutch elm diseasehawthorn hawthorn rust, quince rustlinden Verticillium wiltmaple anthracnose, fungal leaf spots, tar spot, Verticillium wiltoak anthracnose, oak leaf blister, oak wilt, Tubakia leaf spotpeach peach leaf curlplum black knot, plum pocketspoplar Marssonina leaf spotsycamore anthracnose

ConiferousTreesfir Diplodia (Sphaeropsis) canker, rust, Swiss needle castjuniper Cedar apple rust, Kabatina tip blight, Phomopsis tip blightpine brown spot needle blight, Diplodia (Sphaeropsis) canker and tip blight, Dothistroma needle blight, pine wilt, sooty moldspruce Cytospora canker, Rhizosphaera needle cast

FruitsandVegetablesapple apple scab, cedar-apple rust, fire blight, flyspeck, quince rust, sooty blotch, white rotbean Fusarium wilt, white moldcucurbits angular leaf spot, bacterial wiltgrape anthracnose, black rot, bunch rotraspberry anthracnose, Septoria leaf spot, Verticillium wiltstrawberry Mycosphaerella leaf spot, Verticillium wilttomato bacterial spot, blossom end rot, Fusarium wilt, Septoria leaf spot, white mold

Ornamentalsconeflower aster yellows, Verticillium wilt, Septoria leaf spotgeranium bacterial blight, Pythium root and stem rot hosta anthracnose, Arabis mosaic virus, Hosta Virus X pansy black root rot rose black spot, powdery mildew, rose rosette

FieldCropsalfalfa Aphanomyces root rot, spring black stemcorn anthracnose, ear rots (Aspergillus, Diplodia, Fusarium, and Giberella), Fusarium crown rot, gray leaf spot, Holcus spot, Pythium root and crown rot, rust, stalk rot, Stewart’s diseasesoybean bacterial blight, bean pod mottle virus, brown stem rot, Cercospora leaf blight, downy mildew, frogeye leaf spot, Fusarium root rot, Fusarium wilt, Phomopsis seed decay, Phytophthora root rot, pod and stem blight, soybean cyst nematode, sudden death syndrome, top dieback

Turfgrassturfgrass anthracnose, brown patch, gray leaf spot, leaf spot and melting out, powdery mildew, Pythium blight, red thread, rust, summer patch

Rashelle Matthiesen-Anderson, student worker, and Christine Engelbrecht, Plant Disease Clinic diagnostician

Fairy ring of mushrooms

Sulfur shelf fungus

Cedar-hawthorn rust galls on cedar

Freeze injury on ginkgo