The PLASMO Project

Plasmo Project

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Information

THE MODEL
The model simulates the infection cycle development and diseased leaf area. This one represents a topic step, because it is related to the economic threshold of fungicide application. Data required for the simulation, temperature, relative humidity, rainfall, leaf wetness, can be collected from standard agrometeorological station with hourly step. In such a way the obtained information is related to the real pathogen development and it allows to identify the most suitable protection techniques. The initial system status is described by bud break date. This can be easily observed in the field when more than 50% of buds are broken showing little leaves. As an integration of bud break date, it is possible to insert, at any time during the growing season, the leaf area and the disease intensity measured in the field. The model simulates the most important phases of biological cycle of pathogen and determines the timing and the intensity of each infection. The results are expressed in percentage terms, indicating the leaf area covered by the typical lesion determined by the downy mildew, called oil spot.

HOW PLASMO WORKS

INPUT DATA FILE
Before to run the program you need to prepare the file with input data.
You can prepare it with a spreadsheet (like MS Excel ©) filling the column as explained below and saving it as text file delimited by tabulation or comma or space.

The input file has to be prepared with hourly time step. Missing values are NOT accepted:

  • the year (4 digits) in the first column;
  • the Julian day in the second column;
  • the hour of the day in the third column;
  • the hourly temperature (°C) in the fourth column;
  • the hourly relative humidity (%) in the fifth column;
  • the hourly rainfall (mm) in the sixth column;
  • the hourly leaf wetness (0=dry, 1=wet) in the seventh column.
1995 110 0 15.32 82.02 0 0 
1995 110 1 15.29 80.95 0 0 
1995 110 2 15.28 81.05 0 0 
1995 110 3 15.27 80.13 0 0 
1995 110 4 15.16 80.23 0 0 
1995 110 5 14.76 81.77 0 0 
1995 110 6 14.49 81.36 0 0 
1995 110 7 14.58 80.84 0 0 
1995 110 8 15.63 75.83 0 0 
1995 110 9 16.23 70.81 0 0 
1995 110 10 16.54 68.04 0 0 
1995 110 11 17.16 67.28 0 0 
1995 110 12 18.16 62.11 0 0 
1995 110 13 19.32 59.49 0 0 
1995 110 14 20.32 56.22 0 0 
1995 110 15 17.34 71.48 0 0 
1995 110 16 15.95 81.87 0 0 
1995 110 17 15.09 90.73 0.4 0 
1995 110 18 14.51 93.95 0 0 
1995 110 19 14.05 96.67 0 1 
1995 110 20 15.18 99.23 0.8 0 
1995 110 21 14.41 100 0.2 1 
1995 110 22 13.97 100 0.2 1 
1995 110 23 13.64 100 0 1 
Example of input data file.

DATA SET MANAGEMENT
The data set management (METEO button) allows the upload of the input data file prepared before. Once completed the form, providing all information requested, your dataset is ready to be processed by the model.

START CONDITIONS SETTING
When you enter in the model procedure (PLASMO button) you can set three different conditions. The measured leaf area, the observed disease intensity and the budbreak day.
Budbreak day is required by the model to start the simulation. It can be easily observed in the field when more than 50% of buds are broken and show little green leaves. As an alternative to bud break date, it is possible to insert, at any time during the growing season, the leaf area measured in the field with the day of the year. This datum can be directly obtained by using a leaf area meter or can be estimated by applying existing geometrical relationships between the area of each leaf and its dimensions. The unit is square cm per shoot.
The measure of disease intensity represents the input for the model together with the day of the year. This measurement can be performed, as explained before, during primary infection, but this information can be omitted. In this case, the primary infection will be calculated by the model from the meteorological dataset.
The disease intensity date must follow the date of budbreak or eventually of leaf area measurement. The date of budbreak or eventually of leaf area measurement must follow the date of the first day of the input data file.
Some parameters have been set with default values: it is however possible to act on these values in order to match specific biological and environmental conditions.

CALCULATE WINDOW
Pushing the button "Start the model" in the Plasmo window you will open the Calculate window.
Here you can find generic information about the dataset to be processed and the summary of the parameters used in the simulation. For each of the three output sections "INPUTS", "BIOLOGICAL OUTPUTS" and "OPERATIONAL OUTPUTS", you can choose text windows and/or graphic windows.


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