Serious infestations of Xylosandrus germanus (Blandford, 1894) (Coleoptera: Curculionidae, Scolytinae) in chestnut plantations of North-Western Italy

Abstract

Serious infestations of Xylosandrus germanus (Blandford, 1894) (Coleoptera: Curculionidae, Scolytinae) in chestnut plantations of NorthWestern Italy In the Spring 2018 large infestations of the Asian ambrosia beetle Xylosandrus germanus were observed in various chestnut plantations in province of Cuneo (NW Italy). Unexpected thermal increase recorded in April triggered massive colonization of young Euro-Japanese hybrids chestnuts planted in 2017. The attacks spread in a wide western territory of the Cuneo province (Valle Infernotto, Valle Varaita, Saluzzo plain, Valle Po), causing the death of about 25% of the trees growing in the plantations affected by the infestations. Prompt clearcut and destruction of the infested trees, and the laying of attractive traps is needed to contain the damage and reduce the pest population density. Continuous monitoring of the physiological conditions of young chestnut trees and of the pest population is required in order to prevent new outbreaks.

TaqMan probe assays on different biological samples for the identification of three ambrosia beetle species, Xylosandrus compactus (Eichoff), X. crassiusculus (Motschulsky) and X. germanus (Blandford) (Coleoptera Curculionidae Scolytinae)

“…The economic importance of X. germanus is relevant in the USA, where it causes consistent damages in nurseries (Ranger et al 2016 ), apple orchards (Agnello et al 2017 ) and black walnut stands (Katovich, 2004 ); in Europe, its importance is related to outbreaks in forests (Bruge, 1995 ; Galko et al 2019 ; Inward, 2020 ) and in the Mediteranean maquis (Contarini et al 2020 ) but damages have been observed also in Italy on walnut (Stergulc et al 1999 ) and chestnut plantations (Dutto et al 2018 ). Moreover , X. germanus is considered a threat to the biodiversity of autoctonous Scolytinae communities (Henin and Versteirt 2004 ; Bouget and Noblecourt 2005 ), presumably because its niche overlaps with that of the indigenous species.…”

First record of Xylosandrus germanus (Blandford) (Coleoptera: Curculionidae, Scolytinae) in the Mediterranean scrubland in Southern Italy, and its co‐presence with the co‐generic species X. compactus (Eichhoff) and X. crassiusculus (Motschulsky)

“…Liebl) and coniferous trees (CABI, 2020). In Italy, X. germanus was reported mainly in the northern part of the peninsula, preferentially associated with chestnut stands (Rassati et al , 2016; Dutto et al , 2018). Interestingly, this association was recently confirmed in spring 2018 in a chestnut coppice stand in Viterbo province, central Italy, suggesting the spread of this alien species southward across the Italian peninsula (Rassati et al , 2020).…”

“…Here, evergreen shrubs and trees suffered strong and quick desiccation of the small‐diameter branches (up to 3 cm) caused by the wood‐boring activities of the beetles and their associated fungal pathogens (Vannini et al , 2017). A third species, X. germanus, was first reported in northern Italy in 1992 in stands dominated by chestnuts ( Castanea sativa Miller; Bernabò, 2000; Dutto et al , 2018), then in walnut plantations ( Juglans spp. ), in mixed broadleaf stands and in apple orchards (Stergulc et al , 1999).…”

Eficacitatea a două insecticide în prevenirea atacului de Xylosandrus germanus (Coleoptera: Curculionidae, Scolytinae), în condiții de teren

“…Chiar dacă până acum în România nu a fost semnalat decât un singur caz de atac provocat de această specie, într-o livadă din partea de vest a țării (Olenici et al, 2022), pe baza informațiilor din literatură (Heidenreich 1964, Maksymov 1987, Graf și Manser 2000, Zach et al 2001, Böll et al 2005, Agnello et al 2015, 2017, Ranger et al 2016, Dutto et al 2018, Galko et al 2019, Hauptman et al 2019, Ruzzier et al 2021) ea ar trebui să fie considerată un potențial dăunător în păduri, livezi și podgorii (Olenici et al, 2015).…”