THE LATE BLIGHT MODELING SOFTWARE « Pameseb Late Blight »

Pameseb a.s.b.l http://www.pameseb.be

Walloon Agricultural Research Center http://www.cra.wallonie.be

Armstatehydromet and Ministry of Agriculture Yerevan, March 2012

The software will allow you to: -detect the periods that are favourable to the infection -measure the lenght of the incubation phase -detect the day where the fructification phase can happen

⇒Help you to decide if the fungicide application is usefull or not

What does this software contain?

- The documentation file - The parameters file (« parameters.txt ») - The configuration file (« config.txt ») - The « input » folder that contains your weather datas - The modeling software (« Start_modeling ») - The « output » folder that contains the modeling results - Others files that contain tools used by the software

The parameters file.

Defines the values of the main parameters (RH, t ) to be considered for the modeling of the development of the disease

⇒ Do not change these values!

The wetness of the leaves is needed for the development of an infection process. How to measure this leaf wetness? - by measuring RH - by measuring rainfall - by measuring directly the wetness on the leaves

The parameters file.

The relative humidity: - if RH ≥ 90% during a one hour period, then the leaf can considered to be wet - if RH <90% but ≥ 85% and one of the 3 last hour is with RH≥90%, then the leaf has to be considered wet during this 3 hours period

The rainfall: - if rainfall ≥ 0,1mm during a one hour period, then the leaf can considered to be wet during this period

The leaf wetness: - if leaf wetness > 0 during a one hour period, then the leaf can be considered as wet during this period

The parameters file.

How to detect a possible infection? And whit which level of gravity?

= combination of the temperature values and the duration of the wet period

Day average temperature Light Medium Strong Very strong

7 16,5 19,5 22,5 25,58 16 19 22 259 15,5 18,5 21,5 24,510 15 18 21 2411 14 17,5 20,5 23,512 13,5 17 19,5 22,513 13 16 19 21,514 11,5 15 18 2115 10,75 14 17 2016 10,75 13 16 1917 10,75 12 15 1818 10,75 11 14 1719 10,75 11 13 1620 10,75 11 12 1521 10,75 11 11,5 13

With a day mean temperature of 10 C and a wet period of 18 hours, there is a potential infection with a medium level of gravity

The parameters file.

How to calculate the lenght of the incubation period?

= the lenght is in relation with the daily mean temperature. Each day, the model calculate an incubation value which is related to the day temperature. The daily values are cumulated until they reach the value 7 which indicates that the fructification phase can occur .

Daily mean temperature

ranges

Daily value for incubation or

development of infection

-99 to 7,9 °C 0,008 to 12,0 °C 0,75

12,1 to 16,5 °C 1,0016,6 to 20 °C 2,0020,1 to 30 °C 1,0030,1 to 99°C 0,00

With a day mean temperature between 12,1 C and 16,5 C, the incubation value given by the model is 1

The configuration file

-The software is already configured and will run without any change -If you want to change something in (i.e change the measures names,…), you have to edit the configuration file and change what you want, but it is better to change nothing -Before to change something, be sure to make before a copy of the folder « Pameseb Late blight » somewhere on your hard disk. So in case of problems you will have a solution to use again the software.

What does the configuration file define?

-The measures to use (RH and Rainfall or leaf wetness and Rainfall, or both): default value is 1 (RH and Rainfall) -The name of the measures (time = timestamp – temperature = tsa, - RH = hra – Rainfall = plu) -The name of the « input » folder (weather datas): default value = « _input » -The name of the « output » folder (results): default value=« _output » -The maximum size of each weather data file in megabyte (4) -Date format used in weather data files: day (1-31), month (1-12), year (XXXX), hour (00-23), minutes (00-59), seconds (00-59) with the default value « day/month/year-hour:minute:second » -The Leaf Wetness scale

The « input » folder.

-The input folder contains the weather data files -The weather data files must contain the hourly data for:

- the time: « timestamp » -The temperature: « tsa », measured at 1,5m above the soil in degree Celsius -The Relative Humidity: « hra », in % -The rainfall: « plu », in mm -(The Leafwetness: « hct »)

-Each data file name must finish by « .txt »: then if your original file is a « .xls » file, you must save it as « .txt » file -You can choose the rest of the name, the results will be named in the same way -The columns must be separeted by a comma, a semi-colon or tabulation (see examples) -The decimal numbers must use dots (not commas) -The first line must contain the title of each parameter (« timestamp », « tsa »,…) -The weather data file can contain others type of measures, they will be ignored -The column order does’nt matter -The size of each file is limited in order to avoid computer scratch -Take care that your « input » folder contains only the files for which you want to have the results.

Modeling.

-After you have placed your weather data files in the « input » folder, dubble click on « Start Modeling » -The software will run for each file with « .txt » extension placed in the « input » folder -Wait until « End », check if there is no « Error » and press « Enter » to close

The « output » folder.

-After you have closed the « Modeling », open by dubble click the « output » folder -You will find 3 types of files per weather data file in the box:

-File.png: graph with the modeling results -File.csv: data file that you can open with Excel -File.itx: data file that you can open with Igor (software for data analysis)

-The « .CSV » file contains two series of data: - the first one shows the t , RH and rainfall values and also the duration of the wet period and infection gravity - in the second serie, under the first, you will find the incubation curves values

The « output » folder.

File.png : ⇒ graph on which you can follow easily the late blight situation on the period corresponding to your original Excel file ⇒Graph that allows you to decide when a fungicide protection of the field can be usefull.

Infection and level of gravity

rainfall

Incubation curve

RH curve

T curve

Cumulated daily rainfall

The « output » folder.

File.csv : ⇒ data file which can be open by Excel ⇒ contains two datas series:

• the first one shows temperature, humidity, rainfall daily values, the duration of the wet period and the infection gravity • the second one, below the first, shows the daily incubation values

Date,Incub0,Incub1,Incub22011-04-01 00:00:00,0.00,0.00,0.002011-04-01 01:00:00,0.00,0.00,0.002011-04-01 02:00:00,0.00,0.00,0.002011-04-01 03:00:00,0.00,0.00,0.002011-04-01 04:00:00,0.00,0.00,0.002011-04-01 05:00:00,0.00,0.00,0.002011-04-01 06:00:00,0.00,0.00,0.002011-04-01 07:00:00,0.00,0.00,0.00

Date tsa hra WetPeriod plu Infection1/04/2011 0:00 10.90 100.00 1.00 0.10 0.001/04/2011 1:00 10.90 100.00 2.00 0.00 0.001/04/2011 2:00 11.00 100.00 3.00 0.00 0.001/04/2011 3:00 10.90 100.00 4.00 0.00 0.001/04/2011 4:00 10.60 100.00 5.00 0.00 0.001/04/2011 5:00 10.70 100.00 6.00 0.00 0.001/04/2011 6:00 10.80 100.00 7.00 0.30 0.001/04/2011 7:00 10.60 100.00 8.00 0.20 0.00

Date Incub0 Incub1 Incub21/04/2011 0:00 0.00 0.00 0.001/04/2011 1:00 0.00 0.00 0.001/04/2011 2:00 0.00 0.00 0.001/04/2011 3:00 0.00 0.00 0.001/04/2011 4:00 0.00 0.00 0.001/04/2011 5:00 0.00 0.00 0.001/04/2011 6:00 0.00 0.00 0.001/04/2011 7:00 0.00 0.00 0.00

Date,tsa,hra,WetPeriod,plu,Infection2011-04-01 00:00:00,10.90,100.00,1.00,0.10,0.002011-04-01 01:00:00,10.90,100.00,2.00,0.00,0.002011-04-01 02:00:00,11.00,100.00,3.00,0.00,0.002011-04-01 03:00:00,10.90,100.00,4.00,0.00,0.002011-04-01 04:00:00,10.60,100.00,5.00,0.00,0.002011-04-01 05:00:00,10.70,100.00,6.00,0.00,0.002011-04-01 06:00:00,10.80,100.00,7.00,0.30,0.002011-04-01 07:00:00,10.60,100.00,8.00,0.20,0.00

More readable

More readable: select the first column, data, convert, next,comma, next, end.

Other important remarks

Decision to apply a fungicide depends on: -the information displayed by the model: at the end of the incubation phase of an infection process (when value of the incubation curve reaches 5,5 to 6) -other biological parameters

Other biological parameters to take into account: -The first application in the season takes place after the observation of 2 or 3 infection cycles after the general emergence of the crop, except if late blight is already present (observed) in the region (i.e on volunteers, on early crops)

-The first application can be delayed according to the resistance level of the variety ( the first 5 to 6 infection cycles after emergence can be passed)

Other biological parameters to take into account: -The renewal of the protection will depends on:

the residual activity of the last fungicide application: 7 days for the « contact » and « translaminar » fungicides, 10 days for the « systemic » fungicides levels of rainfall: rain can wash the leaves , « contact » fungicides have different levels of resistance against the washing effect of the rain (20 mm to 50 mm)

the development stage of the potato crop: until flowering, the crop produces new leaves every day which have to be protected if needed ( « contact » >< « systemic ») if the vegetative development is intense, the fungicide concentration in the plant decreases and can become not sufficient: in this case the protection renewal can be appropriate (if systemic fungicides are used)

Other biological parameters to take into account: -The renewal of the protection will depends on:

the expected weather: if the scheduled day for the protection will be rainy:

apply your fungicide one day before (systemic, or penetrant) if not possible, apply your fungicide after the rain but use a currative fungicide (metalaxyl, benalaxyl, cymoxanil, or propamocarb)

if the days after the incubation phase are forecasted as dry days (dry and sunny period is forecasted for 10 days), the renewal of the protection can be not necessary)

Don’t put all your confidence in the ouputs of the model, but have a good overview on what happens in the surroundings of the crop:

General emergence date of the main crop Variety resistance When and where the first late blight attacks have been observed Check the crop in the field Take care of particular situations (valley, fields bordered by trees,…) Development stage of the crop Rainfall Weather forecast

Weather stations Net (Automatic catch of weather parameters

on a hourly basis)

Data base for the weather parameters

(valid data!)

Data transfert

Tel, gsm, gprs

Software Late Blight Modeling

RH, t , Rainfall

Infection date Incubation period Fructification date

Output

FINAL DECISION

Fields observations (Emergence date,

First symptoms (where, when), Farmer observations (Specific situations),

…)

Fungicides (Mode of action)

Varieties (resistance level)