Factsheet CPO-model for Septoria in wheat

The CPO Septoria model estimates risk of Septoria tritici blotch infections in winter wheat. Weather data from GS 32 to GS 69 are used. Spraying is recommended after minimum 4 days with rain (> 1 mm) in susceptible cultivars counting days between GS 32 an d GS 69. In resistant cultivars risk of attack is assumed after 5 days with rain (>1 mm) between GS 37 and GS 69. Counting of days with rain goes back a maximum of 30 days. When running the Septoria model the risk for yield losses from other diseases than Septoria 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 Septoria diseases. Only two categories are used: susceptible and resistant. The model does not automatically adjust for the effect of previous fungicide sprays. If a fungicide effective against septoria has been applied in the last 10 days, the risk can be interpreted as low. The DSS is 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 Septoria 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.