First survey on Coraebus undatus Fabricius (Coleoptera: Buprestidae) associated with Quercus ilex L. in Sardinia (Italy)

Abstract: The flathead oak borer, Coraebus undatus (Coleoptera: Buprestidae), is considered
one of main bark beetles associated with oak decline in Europe. The insect has been studied
mainly on Quercus suber L. in Spain where it causes economic damage to the cork industry.
However, its biology and ecology are not yet well known, especially with regard to the other
hosts species. At present no reliable data on diffusion and behavior of this beetle in Italy are
available. This work reports first observations of C. undatus infesting Quercus ilex L. in
Sardinia (Italy). The survey was carried out in 2020 on a sample of Q. ilex trees showing
symptoms of dieback, on which typical signs due to C. undatus feeding activity were observed
on the bark of trunks and branches. In laboratory, adults of C. undatus emerged from samples collected from symptomatic trees. Characteristics of lesions, sub-cortical galleries excavated by larvae, pupal chambers, and emergence holes are described. The results of this study add new insights into biology and ecology of C. undatus, providing useful information to recognize the signs of the C. undatus attacks on holm oak trees. The latter could improve monitoring of C. undatus infestations, allowing to better evaluate the population density of the pest in mixedoak forests and assess its potential spread from infested to uninfested areas.