The INTERFRUTA project and the study of medfly (Ceratitis capitata Wied.) (Diptera: Tephritidae) distribution in the fruit orchards of Terceira Island, Azores

Full text: The INTERFUTA project, which has the goal of enlarging the fruit production, is a project of interregional cooperation between three regions and several institutions, that is financed by the EC program INTERRREG-III-B. In the field, four fruit trees are being studied (orange, apple, peach and banana) in three different sites of Terceira Island fruit production (Angra do Heroismo, Porto Judeu/Sao Sebastiao e Biscoitos). In this project we look it an integrated way at the fruit ecosystem as a whole. Therefore, we analyse all the climactic and all the most important production parameters. We also want to know the fungi and viruses that cause problems in fruit trees, but above all the composition and the dynamics of all the insects present. Special attention is given to the distribution and the life cycle of the medfly, Ceratitis capitata (Wied.) (Diptera: Tephritidae) and its impact in terms of fruit infestation in the different orchards studied. This estimate of the medfly population was done in the three fruit production areas by monitoring the medfly males and females using traps. For the males a sexual pheromone (trimedlure) in Jackson traps was used, and for the females a food-based synthetic lure with a three-component attractant (trimethylamine, ammonium acetate and putrescine) in Tephritraps was used. The estimate of the medfly fruit damage was done using two methods: First, marking the fruits in the trees to determinate the number of fruits damaged, and second, collecting of damaged ruit near the maturation period in the orchards and around the traps and bringing them to the laboratory to determine the number of larvae per kilogram of fruit and the number of larvae registered in each kind of fruit. All this investigation has the goal of contributing to a better knowledge of the medfly population levels, the study of its evolution and appearance to measure the impact of this pest that, in a severe way, limits the fruit production in some of the fruit trees studied. We also attempted to test different ways of monitoring and suppressing the medfly, by testing six different kinds of traps: 'Water Bottle'; 'American; 'Easy Trap'; 'Jackson'; 'Tephri' and 'Israeli'. These traps were tested in two completely distinct orchards, one with homogeneous characteristics in terms of distance between thw trees, and in terms of culture (citrus). The other orchard of heterogeneous characteristics, in terms of distance between the fruit trees and a variety of fruit trees types (loquat, citrus, custard apple, and strawberry guana). The results obtained indicate that the population levels of medfly in the orchards reach their peak near the ripening period of the fruit, normally in mid-summer. The peach was the fruit most affected in the three fruit areas studied. The 'Easy trap' from Sorygar achieved the best results in the male and female-captures using sexual pheromone and food-based synthetic lure, respectively. (author)