1. Weather-based Disease Risk Assessment in Turf Review unique aspects of turf environment Discuss attempts to develop WB systems for turf Describe system used in Indiana / Midwest R. Latin Purdue University

2. Interesting aspects of the turf “environment”... 1. Agronomics... No measureable yield Genetics Cultural options

3. Interesting aspects of the turf “environment”... 2. Economics... Fungicides are expensive Supers spend other peoples’ money Turf grows back!

4. Connecting the dots between environmental variables and turf disease...

5. Gray leaf spot Pink snow mold Dollar spot Brown patch Summer patch Pythium blight Anthracnose

6. Published works describing the use of temperature and moisture variables to predict disease outbreaks* Dollar spot Pythium blight Rhizoctonia blight Anthracnose Gray leaf spot Pink snow mold Summer patch Hall, 1984 (Temp / RH) Smith, 2009 (Temp / moisture) Nutter, 1983 (Temp / LW) Fidanza, 1995 (Temp / RH) Gross, 1998 (Temp / LW) Schumann, 1994 (Temp / RH / Precip) Danneberger, 1984 (Temp / LW) Uddin, 2004 (Temp / LW) Dwyer, 2003 (Temp / M) Anonymous, 1995 (Temp)

7. Data Processor Environmental Data Precip. Hours wetness RH Temp Y = a + b 1 T +b 2 W … Daily Disease Risk Components of Disease Forecasters

8. Examples of on-site data acquisition instruments

9. Environmental data resources… Precip Hours Dew RH Air Temp

10. Data Processor Environmental Data Precip. Hours wetness RH Temp Y = a + b 1 T +b 2 W … Daily Disease Risk Components of Disease Forecasters

11. Weather-based models may be rushed to publication without adequate testing!

12. Environmental risk is based on daily relative humidity and minimum temperatures. To calculate the E-value for a 24 hour period, substitute values for average relative humidity (RH) and daily minimum temperature in degrees Celsius (T) in the equation below: E = -21.5 + 0.15(RH) + 1.4(T) - 0.033(T 2 ) Risk is high if E ≥ 6.0 Brown patch decision rule: E-value Advantages: Convenience 3-5 day forecast Disadvatage: Underestimates risk

13. Data source: SkyBit Algorithms: brown patch / Fidanza (T/RH) Gross (T/LW) Pythium blight / Nutter (T/LW) dollar spot / Purdue (T/LW) Delivery: application server / website