Dasineura oleae: morphological and physiological characterization following the midge attack on olive leaves

Dasineura oleae (Angelini, 1831) (Diptera: Cecidomyiidae), the gall agent of Olea europaea L. leaves, has always been considered just a secondary pest of the olive grove since it does not cause any direct damages on the olive fruits production. However, severe outbreaks were recently recorded in the Mediterranean Basin. Our result shed light on the potential alteration that D. oleae trophic action may trigger on leaf morphology and some physiological activities of olive leaves (O. europaea cv Frantoio), since they are strictly related with the photosynthates accumulation and olives production. Net photosynthesis and stomatal conductance were significantly lower just in infested leaves (P = 0.0038 and P = 0.0487, respectively), inducing to consider that the symptoms of suffering are limited to the attacked organs. Shoot elongation in control versus infested plants shows no difference between the two treatments. Polyphenols content was analyzed in tissues surrounding D. oleae galls, and no deficits were recorded compared to control leaves. Although lab trials reveal no dramatic effects on these physiological activities, further experiments are needed in order to relate physiological alteration in field and olive fruit production.