DISEASE EFFECTS OF

PUSHING CROP ROTATIONS

WITH PULSE CROPS

Sherrilyn Phelps, MSc., P.Ag., CCA, Agronomy Manager,

Jan 24, 2018 – MABA/MGEA

ACKNOWLEDGEMENTS

Dr. Barb Ziesman, Saskatchewan Agriculture

Dr. Syama Chatterton, AAFC Lethbridge

Dr. Sabine Banniza, University of Saskatchewan

TOPICS TO COVER

•Interest in pulse crops

•Pulse crop acres in Northern Great Plains

•Rotations

•Diseases influenced by rotations

• Foliar diseases • Root rots

INTEREST IN PULSE CROPS

• Pea

• Lentil

• Chickpea

• Faba bean

• Dry bean

• Soybean

Source: Dr. Y Gan

N FIXATION

Western Canada

lbs N / acre

Alfalfa 100 - 250

Faba Bean 80 - 160

Pea 50 - 150

Soybean 40 - 140

Lentil 30 - 120

Chickpea 20 - 100

Dry Bean 5 - 70

Source: Dr. J. Schoenau, U of Saskatchewan

100 lbs/acre N @ $0.38/lb = $38/acre

PULSE BENEFITS

N benefit to next crop!

• Microbial decomposition of surface residue, root, old

nodules, root exudates

• N credit of 0.5 to 1.0 lb N/ac for every bu/ac (pea)

higher yields = lower amount

• Benefit to next crop!

% N derived from fixation Source: Dr. J. Schoenau, U of Saskatchewan

PULSE BENEFITS

Non-N benefits

• Stimulate soil biological activity

• Improved soil structure = better root growth

• Improved water holding capacity and drainage

• Break in disease cycles (canola-blackleg, cereals-

fusarium)

• Again…further benefits to the next crop!!

Dr. J Schoenau “ should add $20 to $50/acre credit for pulses”

ROTATIONS

• Crop sequence

• Considerations / drivers

• Economics = Short term gains

• Mitigate risk / insurance

• Long term sustainability / reduce fallow

• Workload

• Manage disease

ECONOMICS: 3 YEAR AVERAGE

ANNUAL NET RETURNS

Preceding Crops 2009

Canola yield

2010

Barley yield

2011

Annual Net Return 2009-2011

_______________ (bu/ac) _________________ ($/acre)

Faba bean (GM) 52 (27%) 91 (14%) 31

Faba bean 41 83 103

Field pea 45 (10%) 84 (6%) 115

Lentils 45 (10%) 85 (7%) 118

Wheat 41 80 68

Canola 37 (-8%) 83 80

*Means reflect data averaged over 5 N rates and 7 western Canada locations

O’Donovan et al. 2014. Agron. J. 106:1921-1932, Khakbazan et al. 2014. Agron. J. 106:2055-2066

MANITOBA CROP INSURANCE

NORTHERN GREAT PLAINS

Padbury et al, 2002

24.7M acres

MONTANA PULSE ACREAGE

PULSE ACRES

(PEA, LENTIL, CHICKPEA, DRY BEAN, FABA BEAN, SOYBEAN)

0

2000000

4000000

6000000

8000000

10000000

12000000

14000000

2013 2014 2015 2016 2017

SK

AB

Montana

PERCENT PULSE ACRES

Location Total cropland 2017 pulse

acres %

AB 20,427,200

2,414,932 12%

SK 38,239,600

7,146,000 19%

MB 9,727,600

2,491,000 26%

Montana 9,100,000

1,799,000 20%

20% = 1 pulse crop every 5 years…..

PLANT DISEASE DEVELOPMENT

Level of host susceptibility: • Variety selection • Plant stand

architecture • Seeding date

The pathogen needs to be present and able to cause disease

Often the biggest driver of disease risk

INTEGRATED PEST MANAGEMENT

Organic agriculture

http://www.unce.unr.edu/programs/sites/ipm/

IPM is a decision making process that uses all necessary techniques to suppress pests*:

IPM

Crop rotation

Variety selection

Seed quality

Seeding date & rate

Equipment sanitation

(clubroot)

Scouting

Foliar fungicides

Residue managment

CROP ROTATION

• Break disease cycles

• Most effective to manage

diseases with:

• Narrow host range

• Soil borne or residue borne diseases

• Less effective for diseases with

long distance spore release &/or

wide host ranges

FOLIAR DISEASES

WHITE MOLD - SCLEROTINIA

• Shows up later (canopy closure)

• Environment - favoured under wet

conditions during flowering; Cool temps.

(15-24° C; 59-75 °F) during & after

flowering

• Rotation management not as effective

as wide host range

Source Dr. B. Ziesman

(Sclerotinia sclerotiorum)

ROTATIONS FOR WHITE MOLD

(SCLEROTINIA)

• Crop rotation >=3 years out of susceptible pulses or

other hosts such as canola or sunflower

• High weed populations (stinkweed, sow thistles, Canada

thistle, wild mustard, redroot pigweed, knapweeds,

dandelions and lambs quarters).

• Rotation management not as effective as wide host range

LENTILS

ANTHRACNOSE OF LENTILS

(Colletotrichum truncatum)

• 2 races: Race 0 & Race 1

• Favoured under wet conditions

• Microsclerotia on soil surface &

residue

• Rain splash spreads from soil

surface and from lesions on

plants

• Crop rotation important

• Fungicide control

Source SK Ag

ASCOCHYTA BLIGHT

(Ascochyta lentis)

• Both seed and stubble borne

• Rotation important

• Spreads from residue to plants

and from plant-to-plant mainly

by rain splash

• Fungicides effective

• Variety resistance

Source Dr. B. Ziesman

DISEASE DECISION SUPPORT

CHECKLIST: ASCOCHYTA & ANTRACNOSE

STEMPHYLIUM BLIGHT

• Tan color canopy

• Widely dispersed pathogen

and could come from

infected seed

• Warm & wet conditions

• Not considered significant in

terms of yield loss

• Fungicides ??

Source: SK Ag

GRAY MOLD - BOTRYTIS

• Develops later in the season after canopy closure

• Soil borne spread by wind (long distance movement)

• Environment - favoured under wet conditions

• Fungicide control but hard to get into canopy

• Heavy canopy can impact

• Rotations less impact

(Botrytis cinerea)

Source: SK Ag

ENVIRONMENT IMPORTANT

Year (Number of Crops)

Percentage (%) of Lentil Crops Surveyed with Disease Symptoms

Root Rot Anthrac-nose

Ascochyta Blight

Sclero-tinia

Botrytis Stemph-ylium Blight

2012 (28)

75 71 32 32 29 36

2013 (37)

65 60 30 32 27 35

2014 (18)

72 83 6 56 0 39

2015 (18)

83 78 0 11 17 50

2016 (50)

70 74 6 86 66 88

2017 (52)

54 38 6 2 0 33

PEAS

MYCOSPHAERELLA BLIGHT

(Mycosphaerella pinodes (Ascochyta pinodes))

• Most common disease of field pea

• Severe epidemics can occur under cool, wet

conditions

• Residue is source of inoculum

• Crop rotation (1 in 3 year minimum)

• Fungicides

• Variety resistance Source: SK Ag

CHICKPEA

WHY CHICKPEA?

• Good standability

• Deep rooted & good drought tolerance

• Resistance to aphanomyces

• Later maturity can spread out harvest

• Pods are quite shatter resistant

• Good marketing options

• $$0.70/lb for kabuli

• Higher risk but high rewards!

Desi

Kabuli

ASCOCHYTA IN CHICKPEA

• Major issue in chickpea production

• Yield loss severe as disease severity increases

• Symptoms visible within 4 to 6 days of infection

• Cool temps (15-25°C or 59-77°F)

• Rainfall >150mm or >6 in.)

(source: Chongo et al., 2003).

Source: adf.farmonline.org.au

ASCOCHYTA IN CHICKPEA

• Seed, soil & residue borne

• Spreads large distance by wind

• Easily spread by physical activity in the field

• Rain splash critical in spore movement and

germination/penetration of fungus

• Rotations/stubble management

• Fungicide application

Source: SK Ag

(Ascochyta rabiei / Didymella rabiei)

Source: adf.farmonline.org.au

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

CHICKPEA ACRES IN SK (1997 TO

2016)

WHY SO QUICKLY LOST CONTROL?

• Limited options for fungicides during 1998-2002

• Increased aggressiveness of disease from 1998 to 2002

• Minimum of 2 apps (up to 7) = >>selection pressure

• Disease moves large distances

• Teleomorph stages (Didymella rabiei) = >> variability in populations

• Variability + selection pressure = resistance to fungicides

Source: Chang 2007

Regina

Swift Current

WESTERN CANADA 2003/2004

• Isolates from S AB • 74% resistant isolates • cross resistance to fungicide classes in 4 isolates

• Chlorothalonil (M5) – Bravo • Macozeb (M3) – Dithane DG • Pyraclostrobin (11) – Priaxor, Headline

Source: Chang et al, 2007

15 races now

WESTERN CANADA 2004-2007

• Random fields

• Petri dish assay

• 2006/07 >>>>> 2004/05

• Resistance to Headline (pyraclostrobin(11)) >> Quadris (azoxystrobin(11))

0

10

20

30

40

50

60

70

80

90

100

2004-05 2006 2007

YEAR OF SAMPLING

PE

RC

EN

TA

GE

sensitive

intermediate

insensitive

0

20

40

60

80

100

120

Headline Quadris

FUNGICIDE TESTED

PE

RC

EN

TA

GE

sensitive

intermediate

insensitive

Source: Bruce Gossen

MONTANA 2016

• 990 isolates

• chickpea, field peas, and

lentil fields

• 11 Didymella rabiei

isolates were resistant

under petri dish

evaluations

• 5 R & 5 S were tested on

plants

Source: Owati et al, 2017

R

S

Dis

ease

Co

ntr

ol

Fungicide [ug/ml]

MONTANA

• Acres increasing • Resistance detected • Planning is going to be key

MANAGING ASCOCHYTA

1. Crop rotation – 76% reduction with 3 non-host crops (Gan 2006)

2. Variety Selection

Source: plantmanagementnetwork.org

6.1 4.5 5.0 ?? ?? ?? ??

2. Seed Quality – (0.3% max)

3. Seed Treatment - kabuli

4. Scout often

5. Disease decision support checklist

6. Apply Fungicide Early

Source: plantmanagementnetwork.org

SYSTEMIC VS PREVENTATIVE

• Timing is critical

• Preventative must go on before disease infection

(source: Shtienberg et al., 2000).

MANAGING FUNGICIDE

RESISTANCE

Can occur when selection pressure is placed on a fungal population

Risk of resistance is highest when:

• Fungicides with a single mode of action

• Pathogens that have a high degree of genetic variation within a population

• Pathogen undergoes multiple spore stages

• Fungicides are used frequently

NOT ONLY CHICKPEA….

Pea (mycosphaerella pinodes) (2011)

• 324 isolates (Northern Great Plains)

• 19 highly insensitive to pyraclostrobin

- 14 AB, 5 SK (0 fr ND, WA)

- R. Bowness

ROTATING FUNGICIDE GROUPS

Adapted from Dr. Sabine Banniza

3 7 11 44 M5

DI carboxamides strobilurins Bacillus chloronitriles

med med high low low

Fungicide Active

Headline EC pyraclostrobin

Quadris azoxystrobin

Quadris Opti azoxystrobin + chlorothalonil

Quadrix Top azoxystrobin + difenconazole

Quilt azoxystrobin + propiconazole

Evito fluoxastrobin

Aproach picoxystrobin

Stratego trifloxystrobin + prothioconazole

Proline prothioconazole

Quash metconazole

Delaro prothioconazole + trilfoxystrobin

Vertisan penthiopyrad

Bravo chlorothalonil

Aprovia Top difenoconazole + benzovindiflupyr

ProPulse fluopyram + prothioconazole

Priaxor fluxapyroxad + pyraclostrobin

Serenade Bacillus subtilis

Endura Boscalid

Chemical Group

Resistance Risk

1. Use multiple modes of action

(See FRAC code lists)

2. Use an appropriate fungicide for

the disease you have

3. Follow label rates

4. Use one application for each

mode of action/chemistry

5. Use an integrated approach

MANAGING FUNGICIDE RESISTANCE

ROOT ROT

THE ROOT ROT PATHOGENS

• Fusarium spp.

• Rhizoctonia spp.

• Pythium spp.

• Aphanomyces euteiches

True Fungi

Fungal-like organisms

Root rots are caused by a combination of different species root rot complex

Fusarium spp. and Aphanomyces euteiches are considered to be the most importance root rot causal agents

PATHOGEN(S)

Figure 1. Schematic relationship among oomycetes, land plants, animals and fungi (adapted from http://www.apsnet.org/edcenter/intropp

/pathogengroups/pages/introoomycetes.aspx).

Fusarium Rhizoctonia Ascochyta Sclerotinia Botrytis

Aphanomyces Pythium Late blight Phytophthora

ROOT ROT FIELD SYMPTOMS

APHAN0MYCES EUTEICHES

• First detected 2012

• Severe issues 2014 & 2016

• Many wet years in a row

• 2 cycles of peas/lentils during

the wet years + past history of

peas lentils = disaster!

Source: Dr. S. Chatterton, AAFC

WHOLE FIELDS AFFECTED

Photo courtesy of L. Reiter

Radisson North Battleford

Photo: S. Phelps

APHANOMYCES EUTEICHES

• Survival of oospores in the soil without a

host for up to 20 years

• Is mobile (zoospores) and can move with

the water

• Favoured by excessive moisture and

temperatures from 22 to 27oC

• Infection can occur anytime during the

season

oospore

http://cronodon.com/images/

zoospore

Source: Dr. Banniza

2010 - peas 2010 - canola

IMPACT OF ROTATION

20 years = 5 x with 1 in 4 year rotations

= 10 x with 1 in 2 year rotations

Opprotunity for pathogens to build up!!!

WATER IMPORTANT

Photo courtesy of Dr. Sabine Banniza, CDC

PEAS = LENTILS

Photo courtesy of J. Ippolito, SMA

Photo: S. Phelps

2014

2016

2017 SITUATION

2017 APHANOMYCES INCIDENCE

ROOT ROT RISK FACTORS

1. Shortened rotation (need 6-8 year break!!!!)

2. Factors that stress plants, delay germination and slow the emergence and growth of plants increase root rot risk

• Wet conditions

• Cool temperatures early in the season

• Soil compaction

• Heavy textured soils

• Nutrient deficiency

A. EUTEICHES HOST RANGE

Crop Disease reaction Oospores

Peas Susceptible Yes

Lentils Susceptible Yes

Cicer milkvetch Susceptible Yes

Dry bean Variable Few

Alfalfa Variable Yes

Chickpeas Resistant Few

Sainfoin Resistant Few

Faba bean Resistant No

Soybean Non-host No

Fenugreek Non-host No

Dr. Sabine Banniza, CDC and Dr. Syama Chatterton, AAFC

SHORTENED ROTATIONS – OTHER

ISSUES

1. Fertility – pulses are not low or no input crops!

2. Weed control - or lack there of / herbicide resistance

Nutrient Removal Rates (lbs/bu)

Nitrogen Phosphorus Potassium Sulfur

Pea 2.3 0.7 0.7 0.3

Lentil 2.0 0.6 1.1 0.2

Chickpea Na 0.36 Na Na

Canola 1.6 0.8 0.4 0.25

Wheat 1.5 0.57 0.33 0.1

KEY MESSAGES TODAY

Learn as much a you can to

make informed decisions

before you get in the field!

1. Rotations are very

important to reduce

inoculum in a field =

prevent disease

2. Other factors are also

important – IPM +

rotating fungicides

THANK YOU – QUESTIONS?

www.saskpulse.com

@SaskPulse

Sherrilyn Phelps

306-480-9767

sphelps@saskpulse.com