Control of fungal diseases in winter wheat with appropriate dose rates and weather‐based decision support systems ¹

Fungicide inputs in cereals have to be reduced, in order to sustain gross margins and reduce environmental side effects. This can be achieved by using fungicide programmes in which doses and timing of fungicides are influenced by detailed knowledge on inherent properties of the fungicides, cultivar resistance and epidemic development of diseases in relation to crop stage and weather conditions. In 1994 and 1995, field trials were carried out in winter wheat in which strategies using full and reduced rates at fixed growth stages were compared with the computerized weather‐based decision support systems PC Plant Protection and PRO_PLANT. A further strategy was included in which timing and dosage of fungicides was based on expert judgement of the interactions of growth stage, disease pressure, weather conditions and cultivar resistance. Effective control of septoria diseases, brown rust and powdery mildew was achieved by all programmes. There was no programme that always resulted in the highest yield and gross margin.