Decision models for the integrated use of fungicides on wheat

Downward pressure on the unit cost of wheat production requires that fungicides should be applied only where an economic return will result. Several decision models have been devised, in the UK and Europe, to allow growers to assess the risk of disease development and hence, tailor fungicide inputs to disease pressure. Field experiments, at six sites in three seasons, tested decision models on varieties of contrasting resistance, under varying pressure from Septoria tritici and powdery mildew. The models tested were: the Bayer Cereal Diagnostic System, the Long Ashton Splashmeter, ADAS Managed Disease Control and a developmental Integrated Disease Risk (IDR) system (the last, designed to the support the use of appropriate fungicide doses). Untreated controls and prophylactic one- and three-spray programmes were also included. Measures of disease control, yield, grain quality and fungicide input costs allowed the performance of systems to be assessed.