The potential implications of climate change for the wheat-aphid-YDV pathosystem

The potential implications of climate change for the wheataphid-YDV pathosystem in WA: a simulation modelling study Hazel Parry1,2, Darren Kriticos1,2, Jean-Philippe Aurambout3, Wendy Griffiths2,3, Garry O’Leary3, Kyla Finlay3, Piotr Trębicki3, Paul De Barro1,2, Jo Luck2,3 1CSIRO

Ecosystem Sciences Research Centre for National Plant Biosecurity 3Department of Primary Industries Victoria

2Cooperative

biosecurity built on science Cooperative Research Centre for National Plant Biosecurity

Wheat-aphid-YDV pathosystem

R. padi BYDV

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CLIMATE CHANGE biosecurity built on science

Large scale

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Climatic niche 2030 Rhopalosiphum padi No risk Endangered (no change or change unknown) Transient (no change or change unknown) No risk (positive change from endangered or transient)

Kriticos DJ and Macfadyen S (in prep)

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Aphids-YDV-climate change Warmer, drier summers Tropical agricultural zone Increased Ryegrass and wheat yield BYDV-RMV and R. maidis increase

Shift in tropical agricultural zone

Parry HR, Macfadyen S and Kriticos DJ (2012) Australasian Plant Pathology

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Small scale

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eCO2 and aphid fecundity Indirect impacts mediated through changes to host plant For R. padi daily fecundity results from the project conflicted with the literature.

Xing et al. 2003.

Daily reproduction increased with eCO2 (350 vs 550 vs 700 ppm)

P. Trebici (CRC project results)

Daily reproduction decreased with eCO2 (350 vs 650 ppm) biosecurity built on science

Wheat biomass under ambient and elevated CO2 and YDV (early) infection: laboratory and field studies Field Results Elevated CO2 increases Biomass

Laboratory Results

Early YDV infection reduces Biomass

eCO2 Field: 550 ppm eCO2 Lab: 650 ppm

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Process-based, mechanistic models Drivers

Temperature Precipitation CO2

Mechanisms

Survival Development Movement Fecundity

Outcomes

Population size and growth Age/size structure Extinction probability Emigrants biosecurity built on science

Avondale case study 1.

2.

3.

Initiation in Irrigated Pasture Wind Dispersal Settling in Wheat

Avondale

Wokalup

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Avondale case study Wheat development accelerates with Climate Change 6

5

3.5 3 2.5 2

2030 relative to 1998

1.5

2070 relative to 1998

1 0.5 0 0

200

400

Day of year

Wheat phenostage

Temperature difference 째C

Climate Scenario CSIRO MK-3 A2 emissions

4 1998 Phenostage 2030 Phenostage 2070 Phenostage

3

2

1

0

1998 CO2 = 350 ppm 2030 CO2 = 450 ppm 2070 CO2 = 620 ppm

0

100

200

300

400

Day of year biosecurity built on science

Wheat impacts Biomass and Yield decline with Climate Change

Biomass 8000

6000 5000

1998 average biomass

4000

2030 average biomass

3000

2070 average biomass

2000 1000

Grain harvest (kg/ha)

6000

7000

Biomass (kg/ha)

Yield

5000 4000 3000

1998 Grain 2030 Grain

2000

2070 Grain

1000 0

0 0

100

200

Day of year

300

400

0

100

200

300

400

Day of year

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Aphid impacts Aphid migration delayed

Migrant arrivals

Aphid population growth accelerates

Population dynamics

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Consequences for wheat yield Projected percentage loss in Grain Yield 2030 and 2070 compared to 1998 with and without YDV

Impact of YDV

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Consequences for YDV impact on wheat

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Summary: WA case study  Climate change = more rapid crop development but lower biomass and yield, most pronounced in 2070.  Climate change is projected to: -

Slow aphid population growth over-summer in grasslands Delay aphid timing of migration Increase aphid population growth rate in crop, leading to Earlier alate (winged morph) formation in crop, due to density

 Synchronisation issues are more important to YDV impacts on yield than the within-crop aphid population growth.  Overall, our simulations suggest YDV impacts on yield will reduce under climate change, although the potential for spread in the crop is greater.

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Thank you  For more information, please email hazel.parry@csiro.au

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