Foliar chickpea issues in2019 in Saskatchewan:

Ascochyta blightand beyond?

Michelle Hubbard, Research Scientist – Pulse

Pathology AAFC Swift CurrentCo-author: Sabine Banniza,

University of Saskatchewan

1CROP DEVELOPMENT CENTRE

• Examples

2019 Symptoms

2

Photos:

M. Hubbard

• Examples

2019 Symptoms

3

Photos:

M. Hubbard

• Examples

2019 Symptoms

4

Photos:

M. Hubbard

• Examples

2019 Symptoms

5

Photos:

M. Hubbard

• Examples

More examples

6Photo: Orion chickpea near Mossbank

by Robert Chewchuk (Syngenta)

• Examples

More examples

7Photo: Orion chickpea near Mossbank

by Robert Chewchuk (Syngenta)

• Examples

More examples

8Photo: Orion chickpea near Mossbank

by Robert Chewchuk (Syngenta)

• Ascochyta blight – clearly present• But why did it come on so fast and so severely?

• Is there something else involved?

• Resistance breakdown

• i.e. genetic resistance in crop being overcome by pathogen

• Environmental

• Herbicides?

• Other disease(s)?

• Root rot

Causes

9

? ? ?

• Caused by Ascochyta rabiei

• Can lead to complete crop loss (Chongo and Gossen 2001, 2003)

Ascochyta blight in chickpea

Chongo and Gossen. 2001. Can. J. Plant Pathol. 23: 358-363

Chongo and Gossen. 2003. Diseases of chickpea. in Bailey et al. eds. Diseases of

field crops in Canada. Can Phytopath Society, Saskatoon, SK.10

L. Shaw

M. Hubbard

L. Shaw

• 0-9 scale

Rating

disease

11

Chongo et al. (2004)

Genetic Diversity of

Ascochyta rabiei in Canada.

Plant Disease. 88: 4-10.

Influence of environment

12Raiz et al. (2017)

• Moisture (Armstrong et al. 2004;

Riaz et al. 2017)

• Temperature

~20°C (Riaz et al. 2017)

Armstrong-Cho et al. 2004. Can J

Plant Path . 26: 134-141

Riaz et al. 2017. Pakistan J Bot.

49: 1971-1974.

• d

13

LifecycleMoisture

needed for

infection

• Fungicides (Gan et al. 2006;

Gossen et al. 2014)

– Financial cost

– Time consuming

– Risk of fungicide resistance

• Especially to strobilurins

14

Current management

Gan et al. 2006. Field Crops Res. 97:121-134

Gossen et al. 2014. Can. J. Plant Path. 36: 327-340

• Crop rotation

• Planting clean seed

• Seed treatments

• Intercropping

• Genetic resistance

‒ Can be overcome

• Colorfulrotations will ↓ risk of resistance developing

Fungicide

resistanceChlorothalonil

Prothioconazile

+ trifloxystrobin

Fluxapryoxad +

pyraclostrobin

Azostrobin +

benzoyindifupyr

Pyraclostrobin

Boscalid

Boscalid +

pyraclostrobin

Fluxapryoxad +

pyraclostrobin

Azostrobin

Metconazole

Azostrobin +

propiconazole

Propiconazole

Prothioconazole

Bacillus subtillis

Penthiopyrad

Syngenta

Syngenta

Syngenta

Bayer

Bayer

Bayer

BASF

BASF

BASF

BASF

BASF

BASF

Nufarm

Corteva

Loveland /

Syngenta

•Assessed strobilurin fungicide resistance by 1) Extracting DNA

2) PCR (polymerase chain reaction)

3) Gel electrophoresis

16

Strobilurin resistance wide spread

Delgado et al. (2013) Plant Path. 62: 688-697

17

Testing for resistance

A sample can contain both strobilurinresistant and sensitive A. rabiei

Delgado et al. (2013) Plant Path. 62: 688-697

• Only 10 diseased fields surveyed (very dry)

• Samples collected later in season

18

Survey in SK in 2018

Field #

Mean

disease

severity

for field

(0-9)

Total

precip.

for 2018

to date

(mm)

Years

since last

chickpea

crop

# of

fungicide

applications

# of

strobilurin

fungicide

applications

Ascochyta

rabiei

confirmed

Strobilurin

resistance

detected

Strobilurin

sensitivity

detected

1 4.0 200 ≥4 6 2 Yes Yes No

2 4.7 192 ≥4 4 2 Yes Yes No

3 5.3 200 ? 4 2 Yes Yes No

4 4.0 84 2 4 3 Yes Yes No

5 2.3 155 2 4 2 Yes Yes No

6 3.3 155 2 4 2 Yes Yes No

7 3.3 127 ≥5 4 2 Yes Yes Yes

8 n/a* n/a n/a n/a n/a Yes Yes Yes

9 n/a n/a n/a n/a n/a No No No

10 n/a n/a n/a n/a n/a Yes Yes Yes

• Things got more complicated!

• 48 fields surveyed

• Every field with confirmed Ascochyta had strobilurin resistance

19

2019 SK survey

n = 17 n = 30 n = 7 n = 17 n = 4 n = 100.0

1.0

2.0

3.0

4.0

5.0

6.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Nu

mb

er o

f fu

ngic

ide

ap

pli

ed

±S

E

Dis

ease

sev

erit

y (

0-9

) ±

SE

All fungicides

Strobilurin-containing

fungicides

Disease

• It’s happened in Saskatchewan before

20

Breakdown of genetic resistance

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

% F

req

uen

cy

LESS Disease (AUDPC) MORE

Aggressiveness of Ascochyta rabiei populations on chickpea cv.

Sanford1998/1999 (0.096/0.35 M acres) 2001 (1.1 M acres) 2002 (0.5 M acres)

Vail and Banniza. 2008. Plant

Pathology. 57 , 665–673

• Chickpea genetic resistance may be breaking down

‒ In CDC Orion, but not CDC Leader

‒ Localized to far south-west

21

Might be happening again in 2019

CDC Leader

Photos: Bunyamin Tar’an, U of Sask

CDC Orion

22

Leader

vs

Orion

L LO O

Far SW

of SK

• Share a resistant parent

• Ascochyta resistance is controlled by many genes

23

Genetic origin of

Orion and Leader

FLIP95-48C FLIP95-48C 93-120-63K X

Adapted to

western Canada

Major source of

A. rabiei resistance

CISN-SP-

99PL21117 X

CDC Orion CDC Leader

Taran, Bandara, Warkentin, Banniza and

Vandenberg. 2011. Can. J. Plant Sci. 91:

355356doi:10.4141/CJPS10172

Taran, Warkentin and Vandenberg. 2013.

Theor. Appl. Genet. 126:1639–1647

DOI 10.1007/s00122-013-2080-2

Major source of

A. rabiei resistance

May make minor contribution to resistance

• Leader and Orion

• Spray with A. rabiei from 2019 fields

• Maintain high humidity

• 3 experiments so far

24

Growth chamber

CDC Leader CDC Orion

• Experiment 1: Planted September 23, inoculated October 22

Growth chamber results -

preliminary

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Leader Orion

Dis

ease

sev

erit

y (

0-9

) ±

SE

13-Nov-19

3-Dec-19

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

11-Nov-19 16-Nov-19 21-Nov-19 26-Nov-19 1-Dec-19 6-Dec-19

Dis

ease

sev

erit

y (

0-9

) ±

SE

Leader

Orion

25

• Sprayed with Ar-2019-011 and Ar-2019-008

• Planted October 11, inoculated Oct 31

26

Growth chamber Exp 2

CDC Leader

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

Leader Orion

Dis

ease

sev

erit

y (

0-9

) ±

SE

Rated by MH

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

Leader Orion

Dis

ease

sev

erit

y (

0-9

) ±

SE

Rated by ZH

• Inoculated with Ar-2019-011

• Planted November 5, inoculated November 21

27

Experiment 3

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

Leader Orion

Dis

ease

sev

eri

ty (

0-9

) ±

SE

Environment

Disease Triangle

EnvironmentTemperature,

Moisture

• Weather

Why the South West?

29

0

50

100

150

200

250

1 1.5 2 2.5 3 3.5 4

Pre

cip

itati

on

(m

m)

Coronach

Assiniboia

Swift Current

Moose Jaw

0%

50%

100%

150%

200%

250%

300%

1 1.5 2 2.5 3 3.5 4

% l

on

g-t

erm

av

e

Coronach

Assiniboia

Swift Current

Moose Jaw

May June July Aug

• Very high humidity in growth chamber

Parallel to growth chamber

30

Photos:

dfd80

82

84

86

88

90

92

94

96

98

100

12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM

Rel

ati

ve

hu

mid

ity

(%

)

• Very high humidity in growth chamber

Parallel to growth chamber

31

Photos:

dfd80

82

84

86

88

90

92

94

96

98

100

12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM 12:00:00 AM

Rel

ati

ve

hu

mid

ity

(%

)

• Even if individual fields follow long rotations

• Inoculum can blow in

Environmental – inoculum build-up

32

0

50,000

100,000

150,000

200,000

250,000

300,000

2008 2010 2012 2014 2016 2018 2020

Insu

red

Acr

es i

n S

K

Chickpeas

Saskatchewan crop insurance data

Zone 3

33

Risk zones

for grain

crops

34

Leader Orion

20

15

20

16

20

16

20

17

20

17

20

18

20

18

Acr

esChickpea area in zone 3

3500

3000

2500

2000

1500

1000

500

0

Saskatchewan Crop Insurance Crop

• Stress can weaken plants → more vulnerable to disease

• Residual, pre-emergent,

• Especially group 14 herbicides

• E.g. Heat (saflufenacil)

• Delayed moisture → uptake by older chickpea

Herbicides

35

“The foliage of sensitive plants turns yellow and brown followed by

death of the whole plant”

-- From Proposed Registration Decision PRD2017-07, Saflufenacil https://www.canada.ca/en/health-

canada/services/consumer-product-safety/pesticides-pest-management/public/consultations/proposed-maximum-residue-

limit/2017/saflufenacil-pmrl-2017-07/document.html

• Stress can weaken plants → more vulnerable to disease

• Residual, pre-emergent, group 14 herbicides

• Heat (saflufenacil)

• Delayed moisture → uptake by older chickpea

Herbicides

36

“The foliage of sensitive plants turns yellow and brown followed by

death of the whole plant”

-- From Proposed Registration Decision PRD2017-07, Saflufenacil https://www.canada.ca/en/health-

canada/services/consumer-product-safety/pesticides-pest-management/public/consultations/proposed-maximum-residue-

limit/2017/saflufenacil-pmrl-2017-07/document.html

Saskatchewan Pulse Growers

• Data from 25 fields

37

Herbicides 2019 SK survey

Herbicide Group Active ingredient

# of

fields Timing

Edge 3 ethalfluralin 4 fall

Rival 3 trifluralin 5 pre-seed or emerg

Glyphosate 9 glyphosate 13 pre-seed or emerg

Valtera 14 flumioxazin 1 pre-seed or emerg

Heat 14 saflufencil 9 pre-seed or emerg

Authority 14 sulfentrazone 6 pre-seed or emerg

Arrow 1 clethodim 5 post-emerg

Centurion 1 clethodim 1 post-emerg

Assure 2 1 quizalofop-p-ethyl 6 post-emerg

Yuma 1 quizalofop-p-ethyl 4 post-emerg

Merge n/a surfactant 4

0

5

10

15

20

25

30

35

40

No Heat Low Heat High Heat Singulation and

Low Heat

Yie

ld (

bu

/ac)

• Field not included in survey

• CDC Orion

• Just 1 field = anecdotal, not scientific

38

Heat and yieldChickpea

yield

(lbs/ac)

Chickpea

yield

(bu/ac)

Southeast 1,497 25.0

Southwest 1,363 22.7

East Central 800 13.3

Provincial 1,391 23.2

10 yr. prov. avg.

(2009-2018)1,316 21.9

SK Ministry of Ag: ttps://www.saskatchewan.ca/business/agriculture-natural-

resources-and-industry/agribusiness-farmers-and-

ranchers/market-and-trade-statistics/crops-statistics/crop-report

• Viruses

• Beet western yellows virus

• Australia chickpea outbreak in 2012 (van Leur et al. 2013 Australian Plant Dis.

Notes. 8: 49-53)

• Pea streak carlavirus

• outbreak in Washington state (Kaiser et al. 1993. Plant Dis. 77: 922-926)

• 16 potential viruses listed by Kaiser et al. 1990 ICRISAT Conference paper

No. CP 587

Other diseases

39

• Fusarium wilt?

• Verticillium wilt?

• No verticillium in any roots with symptoms

Fusarium wilt

Photo: Rachel Long of UC Davis

• Present in only some samples

Root rot

40Photo: M. Hubbard

• Ascochyta blight

• Inoculum build up from growing Orion in 2018

• Strobilurin fungicide resistance

• Possible resistance breakdown…

• Stress (drought, possible herbicide or other pathogens)

• High rainfall

Perfect storm?

41https://image.tmdb.org/t/p/original/aOYHJclz1yZdFT3hdMY8TeYU4fk.jpg

• Do difference in resistance to Ar-2019-011 between Leader and Orion

• Artificial inoculation different from field epidemic

• Other hypothesises:• Ar-2019-011 was not a representative Ascochyta isolate

• Orion more sensitive to some other factor• Herbicide

• Drought and moisture stress

• Another disease

• Root rot

42

What does it mean?

• Avoid Orion in 2020?

• Continue testing hypothesises

• Other Ascochyta rabiei isolates from 2019

• Compare current isolates with older isolates

• Orion and Leader with and without

• Herbicide

• Drought stress prior to inoculation

• Root rot inoculation at the same time as Ascochyta inoculation

43

Next steps

In the growth chamber

44

AcknowledgmentsAAFC Swift Current: Dr. Yantai Gan, Biologist: Zakir Hossain,

Technician: Lee Poppy, Laborers: Eric Walker and Clint Dyck,

Students: Ben Kellough, Alex Menun, Dale Eung, Danielle Beaudoin-Kwan, Ophélie

Grossemy

Government of Saskatchewan, Ministry of Agriculture: Shannon Chant, Kaeley

Kindrachuk, Sherri Roberts, John Ippolito and Allie Noble, Carter Peru, Megan

Pearce

Melanie Leppa, independent agronomist, Soils and Such,

Lyndon Stoll, an independent agrologist of Sustainable Agronomics L.S. Ltd.

Sherrilyn Phelps, Agronomy Manager with Saskatchewan Pulse Growers,

Betty Johnson, Plant Health Officer, SARM

45

Questions?

Comments?

Ideas?