Αn assessment of components of crop loss due to infestation by Dacus oleae, in Corfu

Abstract

An assessment of components of crop loss caused by the olive fly, Dacus oleae, was carried out in Corfu during the years 1976-1979. The results indicate that the most important component of crop loss due to D. oleae infestation is the preharvest fruit drop induced, mainly, by the third stage larva. Using three starting dates, which coincided with the main periods of infestation between July and October, estimates were made of the proportions of infested fruits induced to fall prematurely before the start of harvesting in November. The larva of D. oleae consumes only a small proportion of the fruit pulp (on average 4.48 %). The effect of infestation on the acidity of the oil is indirect and it is important only when the fruits remain for over a week on the ground before they are collected. Compensation by the tree for premature fruit drop caused by D. oleae infestation does not appear to be of any significance in assessing crop loss.