Disease control of irrigated crops

Martin Chilvers Department of Plant, Soil and Microbial Sciences

chilvers@msu.edu @MartinChilvers1 517-353-9967

www.fieldcroppathology.msu.edu

Northern Corn Leaf Blight

Exserohilum turcicum (Setosphaeria turcica)

Gray Leaf Spot

Cercospora zeae-maydis

Gray Leaf Spot

Common Rust

Puccinia sorghi

Northern Corn Leaf Spot

Bipolaris zeicola (Cochliobolus carbonum)

Northern Corn Leaf Spot

Corn fungicide trials

Break-even scenarios for corn Corn price

($/bu)

Application cost ($/A)

$12 $16 $20 $24 $28 $32 $36

$3.00 4.0 5.3 6.7 8.0 9.3 10.7 12.0

$4.00 3.0 4.0 5.0 6.0 7.0 8.0 9.0

$5.00 2.4 3.2 4.0 4.8 5.6 6.4 7.2

$6.00 2.0 2.7 3.3 4.0 4.7 5.3 6.0

$7.00 1.8 2.3 2.9 3.4 4.0 4.6 5.1

$8.00 1.5 2.0 2.5 3.0 3.5 4.0 4.5

$9.00 1.3 1.8 2.2 2.7 3.1 3.6 4.0

$10.00 1.2 1.6 2.0 2.4 2.8 3.2 3.6

2014, Michigan corn fungicide trials

0

20

40

60

80

100

120

140

160

180

200

Untreated Priaxor, 8 ozV6

Priaxor, 8 ozVT

Priaxor, 8 ozV6&VT

Stratego YLD,5 oz V6

Stratego YLD,5 oz VT

Stratego YLD,5 oz V6&VT

Yiel

d (b

u/A)

Coleman

East Lansing

Coleman: DKC38-04RIB , East Lansing: NuTech 5V197 Low levels of Rust, GLS, NLB <1.5 DIX scores

2014, Michigan corn fungicide trials

-30

-20

-10

0

10

20

30

40

Priaxor, 8 oz V6 Priaxor, 8 oz VT Priaxor, 8 ozV6&VT

Stratego YLD, 5oz V6

Stratego YLD, 5oz VT

Stratego YLD, 5oz V6&VT

Yiel

d re

lativ

e to

unt

reat

ed (b

u/A)

Coleman

East Lansing

2015, MSU corn trials – NCLB (DSI)

0

1

2

3

4

5

6

7

8Ea

r Lea

f Dis

ease

Sev

erity

Inde

x

2015, MSU corn trials – Yield (bu/A)

020406080

100120140160180200

Yiel

d (b

u/A)

-50

-40

-30

-20

-10

0

10

20

30

cont

rol

Affia

nce

(10

fl oz

/A) @

V5

Affia

nce

(10

fl oz

/A) @

VT

Dom

ark

230M

E (4

fl o

z/A)

@V5

Dom

ark

230M

E (4

fl o

z/A)

@VT

Equa

tion

SC (6

fl o

z/A)

@V6

Equa

tion

SC (6

fl o

z/A)

@VT

Fort

ix (5

fl o

z/A)

@V6

Fort

ix(5

fl o

z/A)

@V8

Fort

ix (5

fl o

z/A)

@VT

Fort

ix (4

fl o

z/A)

@VT

Head

line

AMP

(10

fl oz

/A) @

V8

Head

line

AMP

(10

fl oz

/A) @

VT

Stra

tego

YLD

(2 fl

oz/

A) @

V5

Stra

tego

YLD

(4 fl

oz/

A) @

VT

Stra

tego

YLD

(5 fl

oz/

A) @

V5 a

nd V

T

Topg

uard

EQ

(5 fl

oz/

A) @

V6

Topg

uard

EQ

(5 fl

oz/

A) @

V8

Topg

uard

EQ

(5 fl

oz/

A) @

VT

Yiel

d de

lta

Early V vs. VT

Corn fungicide conclusions • Variability in data sets and fields:

– Northern states showed high variation—difficult to link yield response to disease severity in all cases

– Some environment related, but yearly variability exists

• Continue to see best economic response from

fungicides when used in response to disease pressure – VT application

Kiersten Wise

Should I be using a foliar fungicide? • On farm trials • Require replication

Goss’s Wilt Remerging Bacterial disease New York Times Sep-30-2013

Goss’s wilt distribution

2013 outbreak in Louisiana

Scouting for Goss’s wilt in Michigan

Why the increase in Goss’s wilt?

• Change in production systems • Corn on corn • Min. or no-till systems • Susceptible hybrids • Change in virulence of the Cmn pathogen • Fungicides are not effective

Tar spot of corn Phyllachora maydis, and Monographella maydis

Only Phyllachora maydis confirmed to date Purdue Diagnostic lab and Kiersten Wise

White mold – 2014

Adjusted to 1bu/A Photo courtesy: Martin Nagelkirk

Peltier et al., 2012

Foliar fungicides – White mold

2014, white mold disease index (DSI)

0

10

20

30

40

50

60

70

80

90

100

Dise

ase

(DIX

)

Disease pressure too high to statistically differentiate treatments

2014, white mold yield

0

5

10

15

20

25

30

35

40Yi

eld

bu/A

Endura 6oz (R1) + Priaxor 4oz (R3); Endura 6oz (R1); Stratego YLD 4oz (R3); Aproach 9oz (R3); Endura 8oz R3; Cobra 6oz + Endura 8oz (R1)

*

2015, white mold trial - Disease

* * *

0

10

20

30

40

50

60

70

80

Whi

te m

old

(DIX

)

• Topsin 30 oz @R1 and R2; • Cobra 6oz + Endura 8oz @R1; • Cobra 6oz @V5

2015, white mold trial - Yield *

0

10

20

30

40

50

60

70

Yiel

d (b

u/A)

Only treatment significantly different to control: Propulse 8oz @R1 + Proline 3oz @R3

When to spray? 2014, application timing

0

5

10

15

20

25

30

Cont

rol

Apro

ach

9 flo

z R2

Apro

ach

9flo

z R3

Endu

ra 8

oz R

1

Endu

ra 8

oz R

3

Yiel

d bu

/A

White mold - Chemical control

• Chemical control as protectant not curative • Application timing to protect flowers up to

beginning pod (R3) • Canopy penetration is essential • Have realistic management expectations

Management of White Mold in Soybean • No silver bullets – must integrate several

management practices: – Partially-resistant varieties

• MSU variety trials www.varietytrials.msu.edu

– Row spacing and seeding population rates

Sudden Death Syndrome (SDS)

SDS has become a significant concern across the Midwest

Complex Disease: • Root rot • Foliar symptoms

Soybean SDS – Michigan

2015

2013

2012

2011

2010

2009

Fusarium virguliforme life cycle

First found Arkansas in 1970

Commercial cultivars – differ in resistance

2014, Yield ILeVO vs. base treatment

-2-10123456

11 2 9 5 6 8 1 7 12 10 3 4Yiel

d re

lativ

e to

bas

e tr

eatm

ent (

bu/A

)

Cultivars

2014, SCN reproduction ratio (Pf/Pi)

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10 11 12

SCN

Pf/

Pi

treateduntreated

SDS management recommendations Prevent movement of infested soil power wash equipment if possible

Confirm it is SDS Utilize resistant varieties ILeVO seed treatment Test and manage for SCN Improve drainage Extended crop rotation may help

Irrigation management for soybeans

Heavy applications favor SDS Many light applications favor white mold

Acknowledgements • Dr. Carl Druskovich, • MSU diagnostic lab, Fred and Jan • John Boyse and Randy Laurenz • Tim Dietz and Kyle Johnson • Kerrek Griffes, Steve Gower - Asgrow • Karen Zuver – Pioneer • Bill Widdicombe and Lori Williams • Midwest colleagues: Kiersten Wise et al.