Securing pulses under changed climates

Potential impacts of foliar fungal pathogensRebecca Ford1 and Kurt Lindbeck2

1Melbourne Sustainable Society Institute & Department of Agriculture and Food Systems,

The University of Melbourne2Wagga Wagga Agricultural Institute,

Industry and Investment NSW

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

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)

2008-092009-10

2010-11

Lentil

Faba Bean

Field pea

Chickpea

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Value ($mAUD)

Area ('oooha)

Production(kt)

2001-2009

2008-2011

Source: www.ABARE.gov.au

Australian pulse productivity• N2 fixation

• disease break• high return export• staple food• moral obligation ~ 40

million• sucker for diseases

Disease threats and costs

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

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

The disease triangle

ENVIRONMENT

PATHOGEN HOST

DISEASE

External environment

rainfall (frequency and volume), temperature, soil conditions, CO2 level, cultural practices, chemicals, vectors

Microclimate

humidity, dew period, temperature, light intensity

Pathogen

fitness, virulence, reproduction, dissemination, population size, adaptive potential

Host plant

architecture, canopy density, resistance genes, additional stress, alternate host

The disease quadrangle

Environment

Genetics

External environment climate changes

atmospheric CO2, heavy unseasonal rain, humidity, drought, winter temperature, cyclones

Phylloclimate

altered timing and periods of leaf wetness, relative humidity, temperature, wind speed, radiation

Pathogen

accelerated pathogen evolution – large and dense canopy = high relative humidity + reduced radiation and wind speed = potential more infection = larger populations = greater chance for beneficial recombination or mutation events

Host plant

growth earlier in season, plant height and branches, thickness and area of leaves, leaf waxes and epidermal thickness

Factors likely to influence disease

severity and spread

Effect of elevated CO2 (700 ppm) on pea plant biomass

Source: Saman Seneweera

• Early growth stage and cultivar specific• Reproducible in the field (Ag-Face)?• Physiology association?

Flooding in Wagga Wagga – December 2010

Water-logged paddocks in Tamworth August 2010 (Source: Kevin Moore I&INSW)

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Rainfall events and volumes on northern NSW chickpea crops 2008 vs 2010

Source: Kevin Moore I&INSW

• 10 fungicide applications • ran out of chemicals

“Chasing the water” – transformational consequences

Similar occurrence of major chickpea

diseases

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

Ascochyta Blight

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core Northfield B. cinerea

Indianhead B. cinerea

Northfield B. fabae

Indianhead B. fabae

Disease management options under shifting climatesA need for “anticipatory research”

• Changes in farming practices• Earlier sowing to avoid earlier rains at maturity

• Appropriate sowing rate

• Appropriate row spacing

• Chemical usage

• Resistance breeding• Germplasm from regions with predicted climates

• Screening under altered environments

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Leaf wetness period influence

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Spore concentration influence

Back to basics!Botrytis Grey Mould of lentil

Crop Disease and pathogen Predicted influence of climate change on disease

Reference

Barley Powdery mildew – Blumeria graminis

Decrease at higher CO2 Hibberd et al, 1996

Rice Leaf blast – Magnaportha oryzae

I ncrease at higher CO2 Kobayashi et al, 2006

Soybean Brown spot – Septoria glycines

I ncrease at higher CO2 Eastburn et al, 2010

Soybean Sudden death syndrome – Fusarium virguliforme

No eff ect at higher CO2 Eastburn et al, 2010

Wheat Stripe rust – Puccinia striiformis

I ncrease with higher temperature Coakley, 1979; Chakraborty et al, 1998; Milus et al, 2006

Wheat Crown rot – Fusarium pseudograminearum

I ncrease at higher CO2, cultivar and soil water dependant

Chakraborty et al, 1998 ; Mulloy et al, 2010

Predicted disease changes by fungal foliar pathogens on field crops under changed climates

Adapted from Luck et al, (2011) Plant Pathology 60: 113-121

Adapted from Chakraborty and Newton (2011) Plant Pathology 60: 2-14

Ranking risks to crop yield and quality from effects of climate change on foliar borne pathogens

“risk analyses to inspire farmer confidence”

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

Revised disease management guides and adapted cultivars

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

External environment climate changes

Source: Cosmos magazine

The phylloclimate and pathogen-host interaction

Temperature

AntagonistsChemicals

Water and % RH

[CO2] Solar radiation

Host defence responses

95 -100% humidity

95 -100%humidity

95 – 100%humidity

Closed canopy High humidity High leaf wetness

No air movement

No air movement

The microclimate environment

• 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.

Agro ecological zones of the Australian cropping belt

Regions of major chickpea disease

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