Olive Fruit Fly - Damages

Damages

The damages caused by the olive fruit fly are of two types: quantitative and qualitative.

From a quantitative point of view, the damage is caused by larvae of second and especially third stages, by the removal of the significant proportion of the pulp which as a consequence results in reduction in the yield of olives. Part of the production is also lost due to premature falling of the attacked fruit. Olive bites and holes dug by the larvae in the initial phase do not have a significant impact on the yield. In table olives, however, the damage extends to the sterile punctures, which cause the variation in production.

A qualitative aspect to be considered is the significant deterioration in the quality of the oil extracted from olives with a high percentage of attacks by larvae of the third stage. The oil obtained from infected olives has a high acidity level (expressed as oleic acid, from 2% to 10% depending on the percentage of the infestation) and a lower shelf life as it has a higher peroxide value. Secondarily qualitative impairments of varying severity derive from the olive fruit fly attacks due to the arrival of mold through the eclosions. This deterioration in quality is evident in significantly flawed oils obtained from olives harvested from the ground or stored for several days before pressing.