Cone and seed pests of Pinus pinea: Assessment and characterization of damage

摘要

Cone and seed insects have played a key role in the decline of stone pine nut production in Italy. To evaluate the impact caused by native Palearctic and exotic insects, a greater knowledge of pest symptoms is required. During 2008-2009, first and second-year stone pine cones, as well as the seeds produced, were examined in Tuscany (Italy) to assess viability. Insect damage was characterized based on external signs on the cones and seed endosperms, and the impact of recorded insect species on nut production was evaluated. In the current study, cones attacked by anobiid beetles and Dioryctria spp. were observed, as well as asymptomatic dead cones and cones with resin drops and patches, that could not easily be related to a damaging agent. As regards the anobiid beetles, adults of Ernobius parens (Mulsant and Rey) and E. impressithorax Pic emerged from cones in laboratory rearing. A low number of cones damaged by Dioryctria spp. was recorded whereas high percentages of cones showed resin exudates. The presence of resin cannot be definitely related to a damaging agent, although the feeding activity of Leptoglossus occidentalis Heidemann could be one of the reasons. Damage by L. occidentalis was assessed by seed observation. Most of the seeds displayed tissues that had been damaged by this pest.