Luta biotécnica contra as principais pragas da nogueira

Abstract

The concerns and difficulties felt by the farmers to control the main pests of walnut, the codling moth (Cydia pomonella L.) and the leopard moth (Zeuzera pyrina L.), together with the growing concern about food quality, increased the interest on and the development of, new control methods that constitute real alternatives to the systematic use, often irrational, of pesticides. The biotechnical control, namely the technique of mating disruption, appears as a viable alternative, since effective biological or cultural methods for the control of these pests are not available at this moment. This control method reduces gradually the population of the pests, doesn't cause deposit residues on the fruits, doesn't induce resistance and doesn't disturb the beneficial fauna, facilitating the protection of the crop against secondary pests as mites [Panony chus ulmi (Koch)] and aphids [Panaphis juglandis Goeze, Chromaphis juglandicola (Kaltenbach)]. In this work, some results obtained with the use of the mating disruption method during the years 2002 to 2004 will be presented and discussed. These results point towards a high effectiveness of the method, mainly in the control of the leopard moth. However, concerning relatively to the codling moth, the infestation levels observed along the three years were relatively low. The decrease of the population levels of both pests along the three years was evident. The infestation levels were always lower in the plots under mating disruption than in the control plots. This decrease was noticed along the three years of experiments.