Using risk models for control of leaf blotch diseases in barley minimises fungicide use – experiences from the Nordic and Baltic countries

The disease pressure from Pyrenophora teres, Rhynchosporium graminicola, and Ramularia collo–cygni varies widely between years locations, which highlights the need for using risk models to avoid unnecessary use of fungicides. Three were tested in thirty–three field trials during two seasons five countries order validate identify situations favourable barley leaf blotch diseases Nordic–Baltic region. were: Crop Protection Online (CPO), uses number days with precipitation (>1 mm), cultivar resistance data as basis assessments; humidity model (HM) signals a warning after 20 continuous hours high humidity, Finnish net (WisuEnnuste), calculates based on previous crop, tillage method, weather parameters. mostly gave acceptable control yield responses compared untreated reference treatments. In dry season 2018, recommended 88–96% fewer applications than treatments, while 2019, was reduced by 0–76% Based increases, recommendations correct 50–69% one–treatment references 69–80% when used mainly