Global Movements of Rust Pathogens in the Atmosphere Scott A. Isard Departments of Plant Pathology and Meteorology Pennsylvania State University University Park, PA USA 16802 & Joseph M. Russo Senior Research Scientist ZedX Inc. Bellefonte, PA APS Field Crops Rust Symposium; 16 Dec 2011; San Antonio, TX
Long-Distance Dispersal Routes for Fungal Pathogens Red arrows indicate sweeps. Black arrows show leaps and jumps. Redrawn from Nagarajan and Singh, 1990. Annual Review of Phytopathology.
Selected Aerial Dispersal Events of Rusts Cereal rusts and powdery mildew Cereal stem rust Tobacco blue mold Wheat yellow rust Sugarcane rust (1978) Wheat brown and stem rust Coffee leaf rust (1970) Wheat yellow rust (1980) Wheat stem rust pathotypes (1969) Red arrows indicate direct aerial invasions of new territories (first year recorded in brackets) Black arrows indicate periodic migrations of airborne spores in extinction-recolonization cycles Redrawn from Brown and Hovmoller, 2002. Science.
Some Recent Dispersal Events of Field Crop Rusts Stripe rust Sugarcane rust Soybean rust Stem rust Dotted arrows indicate sweeps. Solid arrows show leaps and jumps. Red arrows indicate suspected aerial pathways of soybean rust (2001-present) Brown arrows represents movements of Ug99 stem rust race group (1999-present) Orange arrow indicates suspected areal movement of orange sugarcane rust in 2007 Redrawn from Brown and Hovmoller, 2002. Science. Black arrows indicates movement of stripe rust in 2010
Questions How frequently are there opportunities for rust pathogens to be transported: From locations in the Eastern Hemisphere to the Western Hemisphere? From locations in subtropical regions to the continental interior of North America?
Aerobiota Transport Process Conceptual Model Horizontal Transport Takeoff and Ascent Earth s atmosphere Descent and Landing Preconditioning Earth s surface Impact SOURCE AREA DESTINATION AREA
Synoptic Scale Airflows Govern Transport Direction and Speed Ultraviolet Radiation Turbulent Diffusion and Wind Shear Govern Dilution Turbulent Transport and Dilution in the Atmosphere Survival of Spores while Airborne Temperature and Relative Humidity Vertical Distribution of Spores in Canopy Canopy Density & Structure Wind & Turbulence Time of Spore Release Escape of Spores from Canopy Integrated Aerobiology Modeling System (IAMS) modules Deposition of Spores into a Crop Dry Deposition Due to Wind and Turbulence Wet Deposition Due to Washout by Precipitation Plant Growth Stage of Disease Weather Spore Production Colonization of Crop Temperature & Leaf Wetness Crop Growth Stage Isard et al. 2005 BioScience 55: 851-862.
Observation of Soybean Rust Red color indicates counties with soybean rust PSU & ZedX have been providing daily forecasts of SBR spread for 7 years Accuracy of model output depends on reliable and timely disease observations IAMS Output Wet Deposition of Viable Spores 8 Sept 2007
Field Crop Rust Forecast Bulletins Ensemble Forecasting Team Soybean Rust Disease Risk Map
National Atmospheric Deposition Network Rainwater collector Rainwater collection sites
Maps showing 2007 collection weeks for which rain samples and IAMS output both indicate deposition of P. pachyrhizi urediniospores in the continental interior of North America Isard, S.A., C.W. Barnes, S. Hambleton, A. Ariatti, J.M. Russo, A.Tenuta, D.A. Gay and L.J. Szabo. 2011. Predicting seasonal soybean rust incursions into the North American continental interior using sentinel plot monitoring, spore trapping, and aerobiological modeling. Plant Disease 95:1346-1357.
Questions How frequently are there opportunities for rust pathogens to be transported: 1. From locations in the Eastern Hemisphere to the Western Hemisphere?
Potential Source and Destination Regions Used in Analysis Alaska Aleutian Islands British Columbia Washington & Oregon California Gulf Coast Hawaii Mexico & Central America Northern Chile Central Chile Eastern Canada U.S. Northeast Coast U.S. Southeast Coast Florida Greater Antilles Lesser Antilles Sierra Leone Northeastern South America Southeastern South America United Kingdom Spain/Morocco Nigeria Cameroon Angola South Africa Northern China Southern China Philippine Islands Eastern Australia Southern Chile
Parameters and Input Data for IAMS Simulations - Grid spatial resolution was 0.083 degrees (~ 14 km), - Vertical resolution was defined by the standard pressure levels (1000, 950, 900, 850, 800, 700, 600, 500 hpa) - One hr time step. - National Center for Environmental Prediction Department of Energy Reanalysis 2 data set for the 1998-2007 period - Each simulation was initiated for 1 January 1998 with the daily spore production held constant in source area for the duration of the 10-yr run. - Nine grid cells (equivalent to about 125,000 ha at the Equator), distributed throughout a source area, were assumed to have a healthy crop and rust infection severity of 50%. - Parameters for the spore release and escape, dispersion, mortality and deposition modules were those used in a previous soybean rust study (Isard et al. 2007)
Frequency of Days with Deposition of Viable Rust Spores in Western Hemisphere as Simulated by IAMS for 1998-2007 Averaged for for February January Year 0.3/mo 2.2/mo 9.3/mo 11.6/mo 9.6/mo 16.6/mo 29.9/mo 27.2/mo 3.4/mo 11.5/mo 9.5/mo 0.7/mo 4.1/mo 1.7/mo 1.5/mo 0.6/mo 1.5/mo 0.6/mo 0.4/mo 8.1/mo 9.4/mo 13.7/mo 0.2/mo 0.3/mo 0.1/mo
Frequency of Days with Deposition of Viable Rust Spores in Western Hemisphere as Simulated by IAMS for 1998-2007 Averaged for for February January March April Year May 0.3/mo 0.1/mo 2.2/mo 1.3/mo 2.6/mo 11.6/mo 9.6/mo 9.3/mo 7.0/mo 6.1/mo 16.6/mo 29.9/mo 27.2/mo 22.3/mo 13.0/mo 12.6/mo 3.4/mo 11.5/mo 9.5/mo 2.2/mo 0.1/mo 0.7/mo 4.1/mo 1.7/mo 0.4/mo 1.5/mo 0.6/mo 1.2/mo 2.5/mo 1.5/mo 0.6/mo 0.5/mo 0.4/mo 3.6/mo 8.1/mo 9.4/mo 13.7/mo 16.7/mo 18.0/mo 10.4/mo 0.2/mo 0.1/mo 0.3/mo 0.7/mo
Frequency of Days with Deposition of Viable Rust Spores in Western Hemisphere as Simulated by IAMS for 1998-2007 Averaged for for February January August March June April Year May July 0.3/mo 0.1/mo 0.4/mo 0.9/mo 2.2/mo 1.3/mo 2.6/mo 1.2/mo 1.1/mo 5.4/mo 11.6/mo 9.6/mo 9.3/mo 7.0/mo 6.1/mo 11.0/mo 11.7/mo 8.7/mo 16.6/mo 29.9/mo 27.2/mo 22.3/mo 13.0/mo 12.6/mo 18.4/mo 5.9/mo 1.1/mo 3.4/mo 11.5/mo 9.5/mo 2.2/mo 0.1/mo 1.6/mo 0.7/mo 4.1/mo 1.7/mo 0.4/mo 1.5/mo 0.6/mo 1.2/mo 2.5/mo 1.1/mo 6.5/mo 2.2/mo 1.5/mo 0.6/mo 0.5/mo 2.0/mo 3.5/mo 4.1/mo 3.6/mo 0.8/mo 0.4/mo 0.1/mo 8.1/mo 9.4/mo 13.7/mo 16.7/mo 18.0/mo 10.4/mo 4.7/mo 6.3/mo 2.1/mo 0.2/mo 0.3/mo 0.7/mo 0.1/mo
Frequency of Days with Deposition of Viable Rust Spores in Western Hemisphere as Simulated by IAMS for 1998-2007 Averaged for November 0.2/mo 28.1/mo 10.1/mo 2.7/mo 0.9/mo 0.5/mo 4.6/mo 0.2/mo
Frequency of Days with Deposition of Viable Rust Spores in Western Hemisphere as Simulated by IAMS for 1998-2007 Averaged for for for September November December February October January August March June April Year May July 0.1/mo 0.4/mo 0.9/mo 0.6/mo 1.3/mo 0.2/mo 0.3/mo 1.3/mo 2.6/mo 1.2/mo 1.1/mo 5.4/mo 9.5/mo 5.0/mo 2.2/mo 11.6/mo 9.6/mo 6.1/mo 11.0/mo 11.7/mo 8.7/mo 5.3/mo 7.0/mo 10.1/mo 14.4/mo 9.3/mo 29.9/mo 27.2/mo 22.3/mo 13.0/mo 12.6/mo 18.4/mo 5.9/mo 1.1/mo 0.7/mo 9.4/mo 28.1/mo 30.8/mo 16.6/mo 11.5/mo 9.5/mo 2.2/mo 0.1/mo 1.6/mo 2.7/mo 12.8/mo 3.4/mo 4.1/mo 1.7/mo 0.4/mo 0.9/mo 1.3/mo 0.7/mo 0.6/mo 2.5/mo 1.1/mo 6.5/mo 2.2/mo 0.4/mo 1.2/mo 1.5/mo 0.6/mo 2.0/mo 3.5/mo 4.1/mo 3.9/mo 1.8/mo 0.5/mo 1.0/mo 1.5/mo 3.6/mo 0.8/mo 0.1/mo 0.4/mo 9.4/mo 13.7/mo 16.7/mo 18.0/mo 10.4/mo 4.7/mo 6.3/mo 2.1/mo 0.8/mo 3.3/mo 4.6/mo 7.6/mo 8.1/mo 0.3/mo 0.7/mo 0.1/mo 0.4/mo 0.2/mo
Frequency of Days with Deposition of Viable Rust Spores from Eastern Hemisphere Source Regions in U.S. & Canadian Destination Regions 0.4/mo 0.1/mo 0.3/mo 0.3/mo 0.4/mo 0.2/mo 0.1/mo 0.1/mo 0.1/mo Averaged for All Months in Year 0.1/mo 0.1/mo 0.2/mo Averaged for entire year Simulated by IAMS for 1998-2007
Frequency of Days with Deposition of Viable Rust Spores from African Source Regions in the Caribbean Islands Averaged for entire year 4.1/mo 2.4/mo 4.7/mo 0.1/mo 0.4/mo 0.03/mo 0.01/mo 0.01/mo Simulated by IAMS for 1998-2007
Frequency of Days with Deposition of Viable Rust Spores from African Source Regions in Eastern South America Trade Winds > 90% of days 70-90% of days 70-50% of days 7.9/mo January 15.9/mo 3.2/mo 0.7/mo July 0.4/mo 7.2/mo 5.5/mo 0.4/mo 0.03/mo > 90% of days 70-90% of days 70-50% of days Averaged for entire year 0.03/mo 2.1/mo Simulated by IAMS for 1998-2007
IAMS Model Output 20 21 22 23 24 May 1998 11 12 13 14 15 January 1998
Summary of Insights from IAMS Simulations The frequency of trans-oceanic transport and deposition of viable rust spores in the Western Hemisphere : Europe, north of Pyrenees/Alps low Eastern Asia/Australia low Africa, tropics low Africa, poleward of the tropics high relatively short distance persistent trade winds Regions in the Western Hemisphere that are influenced by the ITCZ have the highest likelihood of receiving viable rust spores from the Eastern Hemisphere high frequency & high intensity deposition events Risk of direct aerial transport of viable rust spores to U.S. and Canada low Risk of aerial transport of Ug99 stem rust spores to Western Hemisphere - low
Questions How frequently are there opportunities for rust pathogens to be transported: 2. From locations in subtropical regions to the continental interior of North America?
Frequency of Airflows with Potential to Move Spores between Regions (% of Days in April & May) 19% 19% 40% 23% 33% 23% 8%
Frequency of Airflows with Potential to Move Spores between Regions (% of Days in June & July) 8% 15% 4% 10% 7% 5% 5%
Frequency of Airflows with Potential to Move Spores between Regions (% of Days in August & September) 3% 8% 4% 4% 10% 8% 7%
Winter Wheat 2010 Harvested Acres by U.S. County Soybean 2010 Harvested Acres by U.S. County Winter Wheat Crop Calendar for Central Texas Plant Soybean Crop Calendar for Delta Region Plant Head Harvest J F M A M J J A S O N D Harvest J F M A M J J A S O N D Risk of long-distance aerial spread of soybean rust less than for wheat rusts during the periods when they could potentially cause crop losses in major North American production regions
Late August Late November
Summary of Insights from Analysis Frequency of strong low-level advection of air northward from the subtropics in North America varies greatly with the seasons: High from early April to June midlatitude cyclones Low from mid-june to mid-september tropical cyclones High after mid-september midlatitude cyclones
Underlying Premises of Aerobiology Forecasting Organisms that use the atmosphere for transport from one geographic place to another, flow within motion systems along routes that are mediated by physical and biological features of the Earth surface. The pathways and timing of flow of biota are to a large degree regular, and thus the movement of organisms in the atmosphere is predictable. x Thank You