Context

The olive fruit fly, Bactrocera oleae, is the most important pest species for this crop in Catalonia. Until the last few years, the most widespread control method was based on chemical aerial treatments with bait, which since 2015 have been used only exceptionally. Therefore, their replacement with other control methods has been evaluated. The mass trapping technique is based on using bait to attract adults, which die when they come into contact with the toxicant in the device used. Its efficacy lies in minimising populations of B. oleae (top photo) from the moment the olive is susceptible to be attacked by the fly. When populations are high, this technique needs to be supported by other control methods. This study was carried out on one farm in each of the olive oil PDOs in Catalonia: Terra Alta (Empeltre and Arbequina varieties), Empordà (Argudell var.), Siurana (Arbequina var.), Baix Ebre-Montsià (Morrut and Sevillenca var.) and Les Garrigues (Arbequina var.). Each farm was divided into three plots where three trap densities per unit area were evaluated (middle photo). This density varied between 10 and 80 traps per ha, according to the varietal sensitivity and population abundance of B. oleae in each area. When necessary, the mass trapping technique was reinforced with chemical treatments, including the fungus Beauveria bassiana and kaolin. The efficacy of the method was assessed by determining the percentage of fruit affected by B. oleae and adult populations.