Innovative strategies in epidemiological studies of hazelnut dieback by using G.P.S./G.I.S. and A.Sp.I.S. technology

[Since the 1980s, in the province of Viterbo (north of Latium), a dieback of the hazelnut tree has caused progressive decay of the plants. Physiological, biochemical and molecular tests on bacterial strains, previously obtained from symptomatic samples of hazelnut branches, have shown some bacterial strains of the “True Erwiniae” group or Pseudomonas avellanae Janse et al. involved in the etiology. In order to analyze the spatial distribution of the disease which affects hazelnut fields in this area and the relationships between different territorial compartments, a Global Positioning System (GPS) was set up to record the diseased plants, in association with the Geographic Information System (GIS) and spatial databases based on Mapinfo , Arcview and Idrisi software. The hazelnut areas mainly affected by dieback disease began to be monitored from 2003 onwards and they have been correlated with historical data on the incidence of dieback over the last 6 years. Furthermore, data acquired in the ground activity was compared with the multiple layers of data supplied by the Latium Region and local Farmer’s Associations (meteorological, geological, hydrographical and agronomical data, and land use) and analyzed by GIS software; digital maps were then been drawn. The results show a certain correlation between the incidence of the disease and some environmental parameters, such as rainfall, winter mean temperature and the elevation of fields. The infrared foliage emission was measured during the main phenological phases of the culture, using a portable spectroradiometer in the field, on both healthy plants and diseased ones, then from the air with an Advanced Spectroscopic Imaging System (A.Sp.I.S) assembled on an airplane. Some health plant indexes, such as Normalized Difference Vegetation Index (NDVI) or Red Edge Mean Slope (REMS) were applied and tested.object Object]