Marcia McMullenDept. of Plant PathologyNorth Dakota State Univ.

Fargo, ND

Leaf Rust Detection in ND Wheat Surveys, 1999-2006

Importance of Surveys ND #1 in spring wheat and durum

production Diseases = severe economic damage Producers need “real time” information to

make informed management decisions Survey data provides such information

+ helps validate disease forecasting models

+ provides information about crop losses/quality; possible shifts in races

Real Time Information Provided

Ag Alerts for Growers Weekly Crop and Pest Report IPM Web Site

ND Wheat Surveys Collaborative Effort: NDSU Extension Area Specialists and 2 NDSU Extension State Specialists

Denise MarkelNCREC

*Roger AshleyDREC

•Greg EndresCREC

•Terry GregoireDevils Lake Area

•Marcia McMullen• Jan KnodelSE area

Funded by ND Wheat Commission, ND Dept. of Ag., APHIS –ARSCooperative Pest Survey

The Wheat Survey Uses Technology to Improve Information Delivery

1. Field Scouts trained in pest ID &scouting methods

Field records go from Excel database to mapping program.

Interpolated Grid map

Bulleted maps

Record fielddata using iPAQsand GPS

2.

3.

738

1053957

847

1039

1471

1341

1147

400

800

1200

1600

1999 2000 2001 2002 2003 2004 2005 2006

# of Wheat Fields Surveyed from 2 Leaf - Soft Dough Stage of Kernel Development

0

10

20

30

40

50

60

70

1999 2000 2001 2002 2003 2004 2005 2006

Occurrence of Wheat Leaf Rust 1999-2006

% of Surveyed Fields Positive for Leaf Rust

Average % Severity of Leaf Rust over all Fields

NWNC NE

SW SC

WCCENT EC

SE

Data Reported the 9 Crop Reporting Districts of NASS (Ag. Statistical Service)

.All counties surveyed in each crop reporting district; at least one field per 10,000 acres

1999 Wheat Leaf Rust in ND Crop Reporting Districts

0

10

20

30

40

50

60

70

80

90

SE EC SC C NE NC NW WC SW

% Fields with symptoms

% Severity

Spring Wheat Variety ResponseSpring Wheat Variety Response - - Leaf Rust in ND ‘99 (Dr. Jack Rasmussen, NDSU)

0 10 20 30 40 50

Grandin

ACBarrie

2398

Gunner

Forge

Reeder

2375

Parshall

Oxen

Kulm

Keene

Russ

Amidon

% coefficient of infectionaveraged over Langdon,Prosper, Carrington;

2375 especially low atCarrington;Reeder especially high atCarrington

Coefficient of infection = severity x reaction type

0

10

20

30

40

50

60

70

1999 2000 2001 2002 2003 2004 2005 2006

Occurrence of Wheat Leaf Rust 1999-2006

% of Surveyed Fields Positive for Leaf Rust

Average % Severity of Leaf Rust over all Fields

National Weather Service Precipitation Map June 2005

Source:NOAA

Wet Weather Favored Diseases~ 1300 wheat fields surveyed

56 fields with > 15% severity;Many with between 6-15%

Statewide: 2005 Wheat Leaf and Stripe Rust

27.5

48.5

5.4

0

20

40

60

% all fields with leaf rust% fields > flag leaf with leaf rust% all fields with stripe rust

Stripe Leaf

Stripe Rust - HRSW Rxs one location data: Hettinger Research Extension

Center 2005

0

10

20

30

40

50

60

70

80

90

100

AlsenBiggRed

HannaOkleeGlenn FryerGrangerSteeleND

GraniteKnudson

BriggsPolarisRussOxenUlen

TrooperDapps

BuckPronto

ReederExpress

% incidence

2005 Leaf Rust – HRSW cont.Dr. Jack Rasmussen & Jim Jordahl, NDSU Plant Path Dept.

3.8

7.3

8.7

11

22.7

26.3

36.7

38.7

0 10 20 30 40 50

Granger

Briggs

Alsen

Granite

Russ

Hanna

Oxen

BiggRed

Coefficients of infection

2005 Leaf Rust – HRSW Dr. Jack Rasmussen & Jim Jordahl, NDSU Plant Path Dept.

0.7

1

1.2

1.3

1.4

1.5

1.7

2

2.5

0 10 20 30 40 50

Glenn

Dapps

Fryer

SteeleND

BckPrnto

Ulen

Knudson

Oklee

Trooper

0

10

20

30

40

50

60

70

1999 2000 2001 2002 2003 2004 2005 2006

Occurrence of Wheat Leaf Rust 1999-2006

% of Surveyed Fields Positive for Leaf Rust

Average % Severity of Leaf Rust over all Fields

10 fields with severity > 15%Most between 1-5%

Questions?Questions?

Photo by Marcia McMullen