Insects collected from wood infested with Pityophthorus juglandis Blackman (Coleoptera Curculionidae Scolytinae) in the Piemonte region, Northwestern Italy

Abstract

The walnut twig beetle, Pityophthorus juglandis Blackman (Coleoptera Curculionidae Scolytinae), and thousand cankers disease are documented in the Piemonte region of Northern Italy for the first time. Northern California is found to be the likely origin of the Piemonte walnut twig beetles based on the comparison of CO1 haplotypes. Multiple species of parasitoids have been reared from black walnut wood infested with the invasive walnut twig beetle. These rearings constitute the first record of the genus Neocalosoter Girault and Dodd (Hymenoptera Pteromalidae Cerocephalinae) in Europe and are likely due to accidental introduction along with the host beetle. Two specimens of Theocolax spp. are described as morphological anomalies with geographical origins unknown.