Weather-based Disease Risk Assessment in Turf Review unique aspects of turf environment Discuss attempts to develop WB systems for turf Describe system.

Weather-based Disease Risk Assessment in TurfWeather-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. LatinPurdue University

Interesting aspects of the turf “environment”...

1. Agronomics...

No measureable yield

Genetics

Cultural options

Interesting aspects of the turf “environment”...

2. Economics...

Fungicides are expensive

Supers spend other peoples’ money

Turf grows back!

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

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

Gray leaf spotGray leaf spot

Pink snow moldPink snow mold

Dollar spotDollar spot

Brown patchBrown patch

Summer patchSummer patchPythium blightPythium blight

AnthracnoseAnthracnose

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)

Data ProcessorEnvironmental

Data

Precip.

Hourswetness RH

Temp

Y = a + b1T +b2W …

Daily Disease Risk

Components of Disease Forecasters

Examples of on-site data acquisition instruments

Environmental data resources…

Precip

HoursDew

RH

Air Temp

Data Processor

Environmental Data

Precip.

Hourswetness RH

TempY = a + b1T +b2W …

Daily Disease Risk

Components of Disease Forecasters

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

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(T2)

Risk is high if E ≥ 6.0

Brown patch decision rule:

E-value

Advantages:•Convenience•3-5 day forecast

Disadvatage:•Underestimates risk

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