Rational arrangement of a network for disease survey on a regional scale

The "Forecasting and Warning System" of the Emilia-Romagna region (Italy) uses information from i) weather stations, ii) biological observation in field and iii) models simulating pests and diseases to advise growers to apply crop protection measures. The field observation network is crucial for the system efficiency. Both the number and the spatial distribution of the fields depends on human and economical resources available; frequently they are sufficient to manage a numbers of fields lower then the optimal one and therefore their spatial distribution increases in importance. In this work, we describe a method for a rational arrangement of biological observation fields on a regional scale: it uses phenological models for plant growth simulation and phytopathological models for disease outbreak prediction, both running using meteorological data available on a 5 km-mesh net, managed by by ARPA (Meteorological Service of Emilia-Romagna Region). For the main pathogens of winter wheat (Powdery mildew, Brown rust, Stripe rust and Scab), a risk index is calculated when host plants are susceptible to infection; then a global risk index is obtained and used to generate a regional map showing homogeneous areas. Methods in arranging fields for biological observation are shown.