VM Blackrot

Last modified by geosens on 2025/03/18 22:16

 The black rot model is monitoring and predicting the risk for an infection with the pathogen Guignardia bidwellii. As the spread of the pathogen is influenced by temperature and several other factors it makes sense to use a time based graph, which displays the necessary information. Three levels of detail (Übersicht, Kombiansicht and Detailansicht) are available to display the data in our black rot model. 

Übersicht

On the very top of the page, you will find the infections of the past days and a prediction for the upcoming days. The information is colorcoded.

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The numerical values represent the daily maximum infection index, calculated based on the duration of the wetness period and the temperature conditions during that time. Higher values indicate a greater severity of the infection event. The severity is indicated using the following color scheme:

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The "Übersicht" displays the following parameters for both the past 15 days and the forecast period:

  • Daily average temperatures, minimum and maximum values, daily precipitation totals, and average relative humidity.
  • Leaf wetness (BN): Wetness phases are shown in blue.
  • Infection index: Visualized with the color scheme described above.
  • Relative susceptibility of the berries in percentage (from BBCH 68 onwards).
  • Leaf count and total leaf area per shoot (light green + dark green areas), as well as the currently growing leaf area per shoot (light green) in cm², based on the leaf area model by Schultz (2003).

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Kombiansicht

The Kombiansicht provides a summary of key information for daily vineyard management. It displays current and historical weather data alongside calculated infection and incubation events in a graph. 

The graphical overview displays the following parameters:

Daily Averages, Minima, Maxima, Precipitation, and Humidity:

  • Daily mean, minimum, and maximum temperatures.

  • Total daily precipitation.
  • Daily average relative humidity values.

Leaf Wetness (LW):

  • Leaf wetness phases are highlighted in blue, making it easy to identify periods of high moisture on the vine canopy.

Infection Index:

  • The infection index is displayed using the described color coding: green (no risk), yellow (moderate risk), and red (high risk).

Relative Susceptibility of Berries:

  • The model shows the relative susceptibility of grape berries in percentage terms starting from BBCH stage 68 (the onset of berry touch).

Leaf Count and Surface Area Per Shoot:

  • Total number of leaves per shoot.
  • Total leaf surface area per shoot (light green + dark green areas).
  • The leaf area currently growing per shoot (light green) in square centimeters.

These values are calculated using the leaf area model developed by H.R. Schultz (Geisenheim University), ensuring estimates of canopy development. 

Detailansicht

The Detailed View provides a high-resolution, hour-by-hour breakdown of key parameters. This data offers precise insights into infection dynamics and environmental conditions. Below is an expanded overview of the features, including incubation and infection metrics:

Inkubation

The "Detailansicht" tracks the progression of the incubation period for both leaves and berries, enabling accurate symptom prediction.

a) Incubation progression on leaves (green color):

  • Symptoms on leaves are expected after an incubation period of 175 degree-days, calculated using daily mean temperatures between 6°C and 24°C.
  • The incubation period ends when the cumulative degree-days reach 175, as indicated by the ending of the green incubation line.

b) Extended incubation progression on berries (red):

  • On berries, the incubation period is extended as berry maturity advances. This is represented by a red line that continues beyond the green incubation line.
  • The incubation period for berries ends when the red line ends.

c) Initiation of incubation:

  • Incubation begins when the infection index exceeds 85 degree-hours, calculated using hourly average temperatures between 5°C and 20°C, for the first time on a calendar day.
  • This start date is visually marked by a purple triangle on the timeline.

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2. Infection Index

The infection index represents a dynamic measure of risk, showing the intensity and timing of infection events. This index helps identify when conditions for black rot infection are met, guiding timely intervention.

3. Meteorological Parameters

The detailed view includes hourly meteorological data critical for understanding black rot risks:

  • Temperature (°C) tracks fluctuations that influence fungal activity.
  • Precipitation (mm) records rainfall that may promote spore dispersal and leaf wetness.
  • Relative humidity (%) highlights favorable conditions for spore germination.
  • Leaf wetness (hours) visualizes periods of surface moisture, crucial for fungal infection.

4. Historical and up to date Data

  • Data for the past 15 days or the chosen dates offers a retrospective analysis of weather conditions and infection events.
  • The forecast period provides predictions of future risk levels and incubation dynamics, supporting forward planning.

5. Visualization of Critical Events

The "Detailansicht" integrates clear visual markers and graphical elements for interpretation:

  • Green and red lines represent incubation periods on leaves and berries, respectively.
  • Purple triangles indicate the start of incubation events.
  • A color-coded infection index highlights risk intensity over time.

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