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

  • PDF / 2,143,334 Bytes
  • 10 Pages / 595.276 x 790.866 pts Page_size
  • 62 Downloads / 163 Views

DOWNLOAD

REPORT


ORIGINAL ARTICLE

Dasineura oleae: morphological and physiological characterization following the midge attack on olive leaves Alice Caselli1   · Alessandra Francini1 · Antonio Minnocci1 · Ruggero Petacchi1 Received: 30 April 2020 / Accepted: 16 September 2020 © Deutsche Phytomedizinische Gesellschaft 2020

Abstract 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. Keywords  Diptera: Cecidomyiidae · Frantoio · Gall · Olea europaea · Photosynthesis · Polyphenols

Introduction More than 13,000 species of insects are classified as gallinducers (Stone and Schönrogge 2003; Espírito Santo and Ferdandes 2007), and among them Cecidomyiidae (Diptera) family is the most representative group worldwide (Espírito Santo and Ferdandes 2007; Huang et al. 2014). Included in cecidomyiids, at least five species are hosted by Olea europaea in the Mediterranean area (Dogănlar et al. 2011). However, just two of them induce the plant to produce malformations on the tissue which they feed and just one of these two is specialized on O. europaea: Dasineura oleae (Angelini, 1831), also known as the olive leaf gall midge (Dogănlar et al. 2011). Even if D. oleae is indigenous in the Mediterranean area and it has always been considered a secondary pest of the olive tree, recent and threating outbreaks induce to consider this midge a severe galler pest of the Mediterranean olive groves (Dogănlar 2011; Simoglou et al. 2012; Picchi et al. 2017). The first larval stage of D. oleae * Alice Caselli [email protected] 1



BioLabs, Institute of Life Science, Scuola Superiore Sant’Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy

feeds on olive leaves stimulating the production of extra tissue and giving rise to deformities and swellings (Dogănlar et al. 2011; Tondini and Petacchi 2019). Premature foliar dropping is recorded in intense infestations, and the