Factsheet DSS leaf blotch in wheat

Leaf blotch diseases of wheat can be caused by septoria tritici blotch (Zymoseptoria tritici) and staganospora nodorum blotch (Parastagonospora nodorum), which are both favoured by wet conditions. Fungicide treatments may need to be applied between stem extension and ear emergence, mainly to protect the upper leaves. Control with help of DSS on platform.ipmdecisions.net. Weather data from GS 31 are used. The humidity model estimates risk of septoria tritici blotch infections in winter wheat. Risk of attack is assumed after 20 hours with continuous wetness. A wet hour is defined as minimum 0,2 mm precipitation in an hour or minimum 85% relative humidity. The assumption is that septoria tritici blotch is present in the crop and periods with high humidity create risk for a damaging epidemic. Dates of key growth stages must be included for your location. To obtain accurate risk predictions it is essential to click on the ‘Edit parameters’ button, enter the estimated dates. These estimated dates can be updated during the season as growth stages are reached. Adding information on fungicide spray dates is vital for the model. After spraying, the model assumes that the crop is protected for 10 days. DSS is created by Aarhus University and SEGES and released in Denmark in 2017. Tested in Lithuania, Norway, Sweden, Finland and Denmark in 2018 and 2019.