This study aims to investigate the effect of management regime on canopy arthropod community of the olive tree (Olea europaea L.).
Field studies were performed in two successive years, 2002 and 2003, in two olive groves, one under organic farming and the other under
integrated protection. The integrated protection grove was sprayed once a year in June, with dimethoate, to control the anthophagous
generation of the olive moth, Prays oleae (Bern.). From April to November of each year, the canopy arthropods were sampled weekly.
PRC method was used to analyse the effect of management regime at the community level and results showed that taxa responded differently
to insecticide application suggesting that the organic grove was a more suitable habitat for the arthropods than the integrated
protection grove. Abundance of arthropods peaked in May and June for both years but, after spraying with dimethoate, decreased significantly
in integrated protection grove, recovering very slowly thereafter. Psocoptera, Miridae, Formicidae and Coccinellidae were the
most sensitive taxa to insecticide application. Their decreasing in abundance was more evident in the second year of the trial. On the
other hand chrysopids showed some tolerance to insecticide applications. These results suggest that the timing of spray is of utmost
importance in reducing the side effects of spraying on beneficial arthropods. Moreover, differences in population susceptibility as well
as in life cycle patterns must be considered.
