Severe damage is caused by the olive fly (Bactrocera oleae (Gmel)) in the Trás-osMontes
region. In order to develop a control strategy, two olive groves for oil production
("Cobrançosa" and "Verdeal") and one for table olive ("Negrinha de Freixo") were
assessed ( 1993-1996). The insect phenology, yield losses and fruit infestation were
evaluated.
The insect's peak flight period occurred during the first half of October. Severe yield
losses due to the pest occurred in 1995, reaching 19 % of the total harvest. It is concluded
that earlier harvesting (second half of September) can avoid substantial losses because the
main period of infestation in all years occurred in October.
