Factsheet DSS CPO model for barley net blotch

The CPO net blotch model is recommending treatments in barley when thresholds are exceeded. The risk of attack is based on visual monitoring using frequency of plants attacked. The disease observation is the percentage of plants showing any infection. For example, if 25 plants out of 100 show even a very small amount of disease and the remaining 75 plants are completely healthy, then the observation is 25%. In susceptible cultivars treatments are recommended at lower incidence levels than in resistant cultivars. If treatments are recommended specific fungicides known to be effective against net blotch should be chosen. When running the net blotch model, the risk for yield losses from other diseases is not considered. If no action is recommended it is advised to revisit the crop after approximately one week to make a new evaluation of the risk. To obtain accurate risk predictions it is essential to click on the ‘Edit parameters’ button and enter information on the cultivar’s susceptibility to net blotch. The model does not automatically adjust risk for the effect of previous fungicide sprays. If a fungicide effective against net blotch has been applied in the last 10 days, the risk can be interpreted as low. Created by Aarhus University and SEGES and released in Denmark in 2000. The whole CPO model has been tested in the Nordic and Baltic countries previously, but this might not have included testing of the specific barley net blotch part. This model may be of use in other countries in Northern Europe, it is important to first test in practice before using the DSS for decision support.