2010 Corn Foliar Fungicides Application Timing Trial

South Central Ag LabClay Center, NE

Tamra JacksonExtension Plant Pathologist

University of Nebraska-Lincoln

Gray leaf spot occurred at very low severity

levels (< 2%) and was the predominant foliar

disease at the end of the growing season at this location. Gray leaf spot reached the ear leaf by early- to mid-August.

2010 Diseases

Common rust developed and was the predominant

early-season disease, likely due to plentiful early-

season moisture. Disease severity (

Southern rust was present and was identified in this

trial on Aug. 12. This disease was observed at very low severity (

Eyespot, common smut and Physoderma brown spot were also present in this trial, but at very

low incidence and severity levels, thus not

justifying ratings for these diseases at this

location in 2010.

2010 Diseases

Goss’s bacterial wilt and leaf blight was confirmed in this trial. This disease

was first observed on Aug. 25 and occurred in

this trial at very low incidence and severity

levels.

2010 Diseases

2010 Foliar Fungicide Trials

South Central Ag Lab, Clay Center, NE

2005-2006

•High clearance sprayer used

•Elevated disease risk

•Continuous corn

•Corn hybrid:

•DKC 61-69 (GLS rating 5/9,”good”)

•Planting date: 5/5/10

•Target plant population of 30,000 plants/A

•6 reps

•20 gpa at 40 psi

•Overhead sprinkler irrigated

•Alley width & row spacing = 30 inches

2010 Fungicide Application Timing Trial in NEGray Leaf Spot Disease Severity (%)

Application Timings: V4 (6-3-10), VT (7-14-10), R1 (7-16-10), R3 (7-30-10)

Rating Date & Growth Stage

Treatment

0

1

2

3

4

5

7/15/2010 R1

7/29/2010 R3

8/12/2010 R4

8/25/2010 R5 (starch line 2/3 up kernel)

Dis

ease

Sev

erity

%(%

tota

l lea

f are

a co

vera

ge)

Non-treated Control

Stratego YLD, 2.5 oz/A at V4

Stratego YLD, 5 oz/A at VT

Stratego YLD, 5 oz/A at R1

Stratego YLD, 5 oz/A at R3

Headline, 6 oz/A at V4

Headline, 6 oz/A at VT

Headline, 6 oz/A at R1

Headline, 6 oz/A at R3

2010 Fungicide Application Timing Trial in NEArea Under the Disease Progress Curve (AUDPC) for Gray Leaf Spot

Non

-Tre

ated

2.5

oz/A

at V

4

June

3

5 oz

/A a

t R3

July

30

6 oz

/A a

t VT

July

14

Treatment &Application

Timing6

oz/A

at V

4

Ju

ne 3

5 oz

/A a

t R1

July

16

6 oz

/A a

t R

1

July

16

5 oz

/A a

t VT

July

14

6 oz

/A a

t R3

July

30

*Treatments with different letters are statistically different. Coefficient of variation is 28.8%

46.1

36.3

22.6

34.7 33.5

42.1

22.1 24.4

43.8

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9

Are

a U

nder

the

Dis

ease

Pro

gres

s C

urve

(AU

DPC

) for

gra

y le

af s

pot

Stratego YLD Headline

abc

e

bcd cde

abc

e de

aba

Non-treated

2010 Fungicide Application Timing Trial in NECommon rust Disease Severity (%)

Application Timings: V4 (6-3-10), VT (7-14-10), R1 (7-16-10), R3 (7-30-10)

Rating Date & Growth Stage

Treatment

0

1

2

3

4

5

7/15/2010 R1

7/29/2010 R3

8/12/2010 R4

8/25/2010 R5 (starch line 2/3 up kernel)

Dis

ease

Sev

erity

%(%

tota

l lea

f are

a co

vera

ge)

Non-treated Control

Stratego YLD, 2.5 oz/A at V4

Stratego YLD, 5 oz/A at VT

Stratego YLD, 5 oz/A at R1

Stratego YLD, 5 oz/A at R3

Headline, 6 oz/A at V4

Headline, 6 oz/A at VT

Headline, 6 oz/A at R1

Headline, 6 oz/A at R3

2010 Fungicide Application Timing Trial in NEArea Under the Disease Progress Curve (AUDPC) for Common Rust

Non

-Tre

ated

2.5

oz/A

at V

4

June

3

5 oz

/A a

t R3

Ju

ly 3

0

6 oz

/A a

t VT

July

14

Treatment & Application

Timing6

oz/A

at V

4

June

3

5 oz

/A a

t R1

Ju

ly 1

6

6 oz

/A a

t R1

July

16

5 oz

/A a

t VT

Ju

ly 1

4

6 oz

/A a

t R3

July

30

101.294.8

75.482.5 85.5

95.888.2 85.7

98.6

0

20

40

60

80

100

120

140

1 2 3 4 5 6 7 8 9

Area

Und

er th

e D

isea

se P

rogr

ess

Cur

ve (A

UD

PC) f

or c

omm

on ru

st

aabc

dcd bcd

abcabcd abcd

ab

Non-treated Stratego YLD Headline

*Treatments with different letters are statistically different. Coefficient of variation is 14.4%

2010 Fungicide Application Timing Trial in NEGray Leaf Spot Progression up the plant (Leaf number on 1-19 scale)

August 25, 2010 rating date (R5, starch line 2/3 up kernel)

Non

-Tre

ated

2.5

oz/A

at V

4

June

3

5 oz

/A a

t R3

July

30

6 oz

/A a

t VT

July

14

Treatment & Application

Timing6

oz/A

at V

4

June

3

5 oz

/A a

t R1

Ju

ly 1

6

6 oz

/A a

t R1

Ju

ly 1

6

5 oz

/A a

t VT

Ju

ly 1

4

6 oz

/A a

t R3

July

30

17.2 16.514.7

15.8 15.216.2

14.2 14.815.7

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4 5 6 7 8 9

Gra

y Le

af S

pot P

rogr

essi

on(L

eaf #

Fro

m P

lant

Bas

e)

a abef

bcd cdefabc

f defabcd

HeadlineStratego YLDNon-treated

*Treatments with different letters are statistically different. Coefficient of variation is 6.4%

2010 Fungicide Application Timing Trial in NEStay Green % assessed on September 12, 2010 R5 reproductive stage (starch line ½ up kernel)

Non

-Tre

ated

2.5

oz/A

at V

4

Ju

ne 3

5 oz

/A a

t R3

Ju

ly 3

0

6 oz

/A a

t VT

July

14

Treatment & Application

Timing6

oz/A

at V

4

Ju

ne 3

5 oz

/A a

t R1

July

16

6 oz

/A a

t R1

Ju

ly 1

6

5 oz

/A a

t VT

Ju

ly 1

4

6 oz

/A a

t R3

July

30

30.732.7

34.4 35.3 33.6

29.233.3

36.6 37.5

0

10

20

30

40

50

1 2 3 4 5 6 7 8 9

Stay

Gre

en %

bcabc ab

ab abc

c

abca a

HeadlineStratego YLDNon-treated

*Treatments with different letters are statistically different. Coefficient of variation is 11.2%

2010 Fungicide Application Timing Trial in NEPush Lodging % assessed on October 5, 2010

Non

-Tre

ated

2.5

oz/A

at V

4

June

3

5 oz

/A a

t R3

Ju

ly 3

0

6 oz

/A a

t VT

July

14

Treatment & Application

Timing6

oz/A

at V

4

Ju

ne 3

5 oz

/A a

t R1

Ju

ly 1

6

6 oz

/A a

t R1

Ju

ly 1

6

5 oz

/A a

t VT

Ju

ly 1

4

6 oz

/A a

t R3

Ju

ly 3

0

33.330.8

28.325.0

22.5

35.0

30.027.5

21.7

0

10

20

30

40

50

1 2 3 4 5 6 7 8 9

Push

Lod

ging

%

Non-treated Stratego YLD Headline

*No statistical differences between treatments. Coefficient of variation is 50.7%.

2010 Fungicide Application Timing Trial in NE500 Count Kernel Weight (g)

Non

-Tre

ated

2.5

oz/A

at V

4

Ju

ne 3

5 oz

/A a

t R3

July

30

6 oz

/A a

t VT

July

14

Treatment & Application

Timing6

oz/A

at V

4

June

3

5 oz

/A a

t R1

July

16

6 oz

/A a

t R1

July

16

5 oz

/A a

t VT

July

14

6 oz

/A a

t R3

Ju

ly 3

0

184.4 184.9 183.1186.0

184.3 182.6 183.2

188.4184.8

150

160

170

180

190

200

1 2 3 4 5 6 7 8 9

500

Cou

nt K

erne

l Wei

ght (

g)

Non-treated Stratego YLD Headline

*No statistical differences between treatments. Coefficient of variation is 2.6%

2010 Fungicide Application Timing Trial in NEGrain Moisture %

Non

-Tre

ated

2.5

oz/A

at V

4

June

3

5 oz

/A a

t R3

Ju

ly 3

0

6 oz

/A a

t VT

Ju

ly 1

4

Treatment & Application

Timing6

oz/A

at V

4

June

3

5 oz

/A a

t R1

July

16

6 oz

/A a

t R1

July

16

5 oz

/A a

t VT

Ju

ly 1

4

6 oz

/A a

t R3

Ju

ly 3

0

15.9 16.0 15.9 16.1 16.0 15.7 15.9 15.9 16.2

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4 5 6 7 8 9

Gra

in M

oist

ure

%

Stratego YLD HeadlineNon-treated

*Harvest date: October 15

*No statistical differences between treatments. Coefficient of variation is 2.2%

2010 Fungicide Application Timing Trial in NEYield (bu/A)

Non

-Tre

ated

2.5

oz/A

at V

4

Ju

ne 3

5 oz

/A a

t R3

Ju

ly 3

0

6 oz

/A a

t VT

July

14

Treatment & Application

Timing6

oz/A

at V

4

June

3

5 oz

/A a

t R1

July

16

6 oz

/A a

t R1

July

16

5 oz

/A a

t VT

Ju

ly 1

4

6 oz

/A a

t R3

July

30

234238

231

243

227231

239

249

225

200

210

220

230

240

250

260

1 2 3 4 5 6 7 8 9

Yiel

d (b

u/A

)

Stratego YLD HeadlineNon-treated

*No statistical differences between treatments. Coefficient of variation is 6.0%

Acknowledgments

• Casey Schleicher, Technologist• Jae Behn, Technologist• Kim Miller, Technician• UNL South Central Ag Lab (SCAL) Staff

Department of Plant PathologyUniversity of Nebraska-Lincoln

Institute of Agriculture and Natural Resources

2010 Corn Foliar Fungicides Application Timing Trial���South Central Ag Lab�Clay Center, NE�Slide Number 2Common rust developed and was the predominant early-season disease, likely due to plentiful early-season moisture. Disease severity (