The use of trap captures to forecast infestation by the olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), in traditional olive groves in north-eastern Portugal

A study was carried out during a three-year period (2006 to 2008) in traditional olive groves in the Terra Quente region of north-eastern Portugal to evaluate the potential of two commercially available traps for predicting infestations by olive fly, Bactrocera oleae (Rossi). We used yellow sticky traps baited with pheromone, and McPhail traps baited with diammonium phosphate. The results show that the variation in infestation is explained by captures of adults in both traps. Thus, even if infestation has changed significantly between years as well as groves and olive tree varieties, captures obtained by both types of trap can be valuable indicators of fruit infestation in Terra Quente, and probably in other regions that have a continental Mediterranean climate. The information obtained can enable growers and consultants to time treatments, and so avoid the use of more labour-intensive visual sampling methods.