Evaluation of the IPM Wheat Model in the Rhineland 2001.

The results of field trials at nine locations with two wheat cultivars in each case demonstrated the practicability of the action threshold-based fungicide strategy of the IPM Wheat Model under the intensive wheat production conditions in the Rhineland. Action thresholds used and dosage of fungicides applied are outlined. Despite using reduced rates of fungicides the epidemic development of relevant pathogens--mainly Septoria tritici and Puccinia recondita--was controlled in early stages of disease development. In plots treated according to the IPM Wheat Model disease incidence and disease severity were reduced effectively compared to untreated plots with low and high disease incidence, respectively. The effective control of pathogens using pathogen-specific action thresholds resulted in yield levels very similar to those of disease-free plots simultaneously minimising the total amount of fungicides applied. Disease control according to the IPM Wheat Model raised yields by up to 25% with monetary benefits averaging more than [symbol: see text] 100 ha-1 in 2001.