Barley Netblotch Model

Photo: E. Fløistad, NIBIO


The disease is caused by Pyrenophora teres (spot form and net form).

The netblotch model is a regression model made by Dr. Oleif Elen based on Norwegian disease assessments, weather and barley variety data that calculates disease development continuously. The start value is put in 14 days after sowing and the disease development calculations start 28 days after sowing. Disease development calculations stop after 900 degree-days (around BBCH 75). The starting value is corrected for by previous crop and tillage. The disease development model runs parallel to a spray threshold model. The main factors driving the disease development model are the amount of precipitation and the number of days with precipitation over 0,2mm between 24 and 14 days before the day of disease development calculation. The threshold model is based on a constant amount of precipitation of 2 and number of days with precipitation of 3. Additionally, the user can enter observed disease severity to adjust the predicted values. Current and 5-day in advance predicted climate data is automatically downloaded from the meterological institute and used for the prediction models.

Fungicide application is recommended once the disease development graph crosses the threshold graph. The model does not include recommendation on the choice of fungicides or the dosage. The prognosis is presented both in a chart and in a table. On the chart, the disease value and threshold value are displayed. Values after the white dotted line are based on weather forecasts. The background color of the chart reflects the warning status. The table contains the values from the chart, and then some weather data for more detailed information. If the observed or calculated disease value is greater than the threshold value, a red sign indicates that the use of fungicides should be considered. The threshold value is an expression of the economic profitability of applying fungicides.

TODO: Add usage

This is technical info for model and web developers

			"timeOfObservation": "2012-05-20T12:00:00+02:00",
			"latitude": "71.0",
			"longitude": "10.0",
			"observedValue": "25.0",
			"denominator": "100.0",
			"name": "Pyrenophora teres"
			"sprayingDate": "2012-06-01",
			"pesticideName": "ACME",
			"sprayingEffectFactor": "0.5"
				"timeMeasured": "2012-03-25T00:00:00+02:00",
				"timeMeasured": "2012-03-25T00:00:00+02:00",