1. Securing pulses under changed climates
Potential impacts of foliar fungal pathogens
Rebecca Ford1 and Kurt Lindbeck2
1MelbourneSustainable Society Institute & Department of
Agriculture and Food Systems,
The University of Melbourne
2Wagga Wagga Agricultural Institute,
Industry and Investment NSW

2. Food security and plant fungal diseases
Past impact of Potato Blight - Phytophthora infestans
• Oomycete (water mould)
• A series of very wet and cooler years prior to the epidemic
• Sole cause of 1845 irish potato famine - 1M people starved, 2M people migrated

3. Current threat from Wheat Stem Rust - Puccinia graminis
• Ug99 – Uganda Africa Asia (in India now)
• The “polio of agriculture”
• Wheat, rice and maize provide 60% of the world’s food energy intake
• China and India - world’s biggest populations AND biggest wheat consumers
• 90% of wheat varieties highly susceptible, 100% crop loss
• 44% yield decrease by 2030 with 1-2oC rise alone in India (Swaminathan)

4. Australian pulse productivity
• N2 fixation
2001-2009 • disease break
• high return export
• staple food
3 000.0
• moral obligation ~ 40 million
2 500.0
• sucker for diseases
2 000.0
2001-02
2002-03
1 500.0 2008-2011
2003-04
1 000.0
2004-05
2005-06
2006-07 500.0
700
2007-08
2008-09 0.0 600
Value ($m Area ('ooo Production
AUD) ha) (kt) 500
Production (kt) 400
300 Chickpea
200 Field pea
100 Faba B ean
0 Lentil
2008-09
2009-10
201 1
0-1
Source: www.ABARE.gov.au

5. Disease threats and costs
Source: Murray and Brennan (2011). Current and potential costs from diseases of pulse crops in Australia. GRDC report

6. Disease control and costs on chickpea
$m AUD
Source: Murray and Brennan (2011). Current and potential costs
from diseases of pulse crops in Australia. GRDC report

7. The disease triangle
ENVIRONMENT
DISEASE
PATHOGEN HOST

8. The disease quadrangle
External environment Microclimate
rainfall (frequency and humidity, dew
volume), temperature, soil period, temperature, ligh
conditions, CO2 t intensity
level, cultural Environment
practices, chemicals, vecto
rs
Pathogen Host plant
fitness, virulence, reproducti architecture, canopy
on, dissemination, population density, resistance
size, adaptive potential genes, additional
stress, alternate host
Genetics

9. External environment Phylloclimate
climate changes altered timing and
atmospheric CO2, heavy periods of leaf
unseasonal wetness, relative
rain, humidity, drought, winte humidity, temperature, w
r temperature, cyclones ind speed, radiation
Factors likely to
influence disease
severity and
spread
Pathogen Host plant
accelerated pathogen evolution – growth earlier in
large and dense canopy = high season, plant height and
relative humidity + reduced branches, thickness and
radiation and wind speed = area of leaves, leaf
potential more infection = larger waxes and epidermal
populations = greater chance for thickness
beneficial recombination or
mutation events

10. Effect of elevated CO2 (700 ppm) on pea plant biomass
• Early growth stage and cultivar specific
• Reproducible in the field (Ag-Face)?
• Physiology association?
Source: Saman Seneweera

11. Flooding in Wagga Wagga – December 2010
Water-logged paddocks in Tamworth
August 2010 (Source: Kevin Moore I&INSW)

12. Rainfall events and volumes on northern NSW chickpea crops 2008 vs 2010
Year 2008
180
160
140
Rainfall (mm)
120
100
80
60
40
20
0
Year 2010
• 10 fungicide applications
50
45
40
• ran out of chemicals
Rainfall (mm)
35
30
25
20
15
10
5
0
1/04/2010
1/05/2010
1/06/2010
1/07/2010
1/08/2010
1/09/2010
1/10/2010
1/11/2010
1/12/2010
Date
Source: Kevin Moore I&INSW

13. “Chasing the water” – transformational consequences
Ascochyta
Blight
Similar occurrence of
major chickpea
diseases
Source: Murray and Brennan (2011). Current and potential costs from diseases of pulse crops in Australia. GRDC report

14. Disease management options under shifting climates
A need for “anticipatory research”
• Changes in farming practices
• Earlier sowing to avoid earlier rains at maturity
• Appropriate sowing rate 9
8
• Appropriate row spacing
7
6
Disease Score
Northfield B. cinerea
• Chemical usage
5 Indianhead B. cinerea
4 Northfield B. fabae
Indianhead B. fabae
3
2
1
0
6week 8week 10week 12week
Time (weeks)
• Resistance breeding
• Germplasm from regions with predicted climates
• Screening under altered environments

15. Back to basics! Leaf wetness period influence
Botrytis Grey Mould of lentil 7.0
6.0
5.0
Disease score
4.0 B. cinerea
3.0 B. fabae
2.0
1.0
0.0
3hr 6hr 9hr 12hr 18hr 24hr 36hr 48hr 72hr
Leaf wetness period
Spore concentration influence
5
4.5
4
3.5
Disease score
3
B. cinerea
2.5
B. fabae
2
1.5
1
0.5
0
100 spores/mL 1,000 spores/mL 10,000 100,000 1,000,000
spores/mL spores/mL spores/mL
Spore concentration

16. Predicted disease changes by fungal foliar pathogens on field
crops under changed climates
Crop Disease and pathogen Predicted influence of climate change Reference
on disease
Barley Powdery mildew – Decrease at higher CO2 Hibberd et al, 1996
Blumeria graminis
Rice Leaf blast – Increase at higher CO2 Kobayashi et al, 2006
Magnaportha oryzae
Soybean Brown spot – Increase at higher CO2 Eastburn et al, 2010
Septoria glycines
Soybean Sudden death syndrome – No effect at higher CO2 Eastburn et al, 2010
Fusarium virguliforme
Wheat Stripe rust – Increase with higher temperature Coakley, 1979; Chakraborty et al, 1998;
Puccinia striiformis Milus et al, 2006
Wheat Crown rot – Increase at higher CO2, cultivar and Chakraborty et al, 1998 ; Mulloy et al,
Fusarium pseudograminearum soil water dependant 2010
Adapted from Luck et al, (2011) Plant Pathology 60: 113-121

17. Ranking risks to crop yield and quality from effects of climate
change on foliar borne pathogens
“risk analyses to inspire farmer confidence”
Adapted from Chakraborty and Newton (2011) Plant Pathology 60: 2-14

18. Revised disease management guides and adapted cultivars
Based on:
• Multifactor studies of climate change
effects on:
• agroecological regions
• disease (pathosystem-specific)
• pathogen population dynamics
• Smarter breeding for resistance
• Better understanding of gene
expression in plants and pathogens
in response to climatic factors
• traditional selective
• GM

20. External environment climate changes
Current changes in the Australian climate
Atmospheric CO2 (88 ppm in 250 years)
mean temperature (0.74 oC in 100 years)
# of warm days
# of cold days and frost events
total annual rainfall (6% in 100 years)
Predicted changes in the Australian climate by 2095 under
the A2 scenario
Atmospheric CO2 (1250 ppm)
mean temperature (3-4 oC )
# of very warm days
# of very cold days and frost events
frequency of severe weather events (flooding, drought, cyclones)
spatially and temporarily heterogeneous rainfall
Source: Cosmos magazine

21. The phylloclimate and pathogen-host interaction
[CO2] Solar radiation
Temperature
Chemicals
Antagonists
Water and % RH
Host defence responses

22. The microclimate environment
No air 95 -100% 95 -100% 95 – 100% No air
humidity humidity humidity movement
movement
Closed canopy High humidity High leaf wetness

23. • Precision agriculture tools
Digital Thermography for Disease Control
Pathogen affects water uptake and translocation = transpiration
and leaf temperature
Infrared thermography detects disease-induced changes in plant
transpiration and water status.
Source: Lenthe (2003). Joint conference of ECPA-ECPLF p477-478.

25. Agro ecological zones of the Australian cropping belt

26. Regions of major chickpea disease
Source: Murray and Brennan (2011). Current and potential costs from diseases of pulse crops in Australia. GRDC report