ABSTRACT
Studies were conducted in different sites of two major potato production areas of Trás-os-Montes : Montalegre and Boticas, ca. 44 km NW and 24 km SW of Chaves, respectively. Influence of climatic conditions between areas as well as of altitude and wood protection within each area on aphid attack was evaluated. Comparison of capture means for the key vector, Myzus persicae (Sulz.), was made between sites of each region. Flight dynamics of green peach aphid, M. persicae, was studied in untreated fields from several localities of Montalegre and Boticas. Seasonal abundance of aphidophagous insects was evaluated on potatoes. To predict flight activity, correlations between logarithm of the number of alatae M. persicae and accumulated day-degrees above 5°C were established. Relationship between number of alate aphids and virus incidence was analysed. On the basis of our results, the most appropriate timing and aphid density at which to apply insecticidal sprays were determined.
