Can increasing infestations by Rhynchophorus ferrugineus threaten endemic Chamaerops humilis in Sardinia (Italy)?

Abstract

The red palm weevil, Rhynchophorus ferrugineus, is the most devastating pest of the Canary palm, Phoenix canariensis, in the Mediterranean Basin. Sporadic infestations have also been observed in other cultivated palm species and, above all, in the endemic European fan palm, Chamaerops humilis. Considering the high ecological importance of C. humilis in coastal ecosystems, the present paper gives an update on the status of R. ferrugineus infestations on the European fan palm in Sardinia (Italy). Since the introduction of R. ferrugineus into Sardinia, attacks of this pest on C. humilis have been limited but have increased in the last 2 years, including infestations on eight naturally growing palms in a Natura 2000 site. Male and female red palm weevils that emerged from C. humilis were similar in size to those of P. canariensis, indicating that the quality of these two feeding substrates is similar. The limited number of infested European fan palms observed so far suggests caution when predicting a rapid spread of this pest in cultivated and non‐cultivated C. humilis palms. Nonetheless, natural populations of C. humilis along western Mediterranean shores should be monitored in order to highlight the potential establishment of R. ferrugineus in these habitats.