Invasive chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae), its native parasitoid community and association with oak gall wasps in Slovenia

Abstract

Abstract. The Asian chestnut gall wasp (ACGW), Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), is a global pest of chestnut trees. This pest was first recorded in Slovenia in 2005. Despite strict phytosanitary measures it was present throughout the country in native chestnut stands by 2013. We provide here the first overview of the parasitoids of ACGW in Slovenia recorded over a 4-year period and the direct interactions between parasitoid communities attacking hosts on chestnut and oaks at the same sites. A total of 27 species of native parasitoids that normally parasitize oak cynipids emerged from ACGW galls. The most abundant species were Torymus flavipes and Eupelmus urozonus. Seven species appear to be geographically well distributed in Slovenia. Twelve species of oak gall wasp were parasitized by 19 species of parasitoids. All native parasitoids have broad host ranges, so a large parasitoid diversity within this community can be expected. This is a novel study comparing the parasitoid communities associated with chestnut and oak galls.

Success of classical biocontrol agent Torymus sinensis within its expanding range in Europe

“…Intensive releases have been made in Veneto region, Italy, since 2010 (Colombari and Battisti 2016), and T. sinensis has covered the distance crossing Slovenia to Croatia and Hungary in 4 years. This rapid dispersal of T. sinensis was aided by high concentration of the host, as well as the lack of competition of native parasitoids (Mato sevi c and Melika 2013; Kos et al 2015;Colombari and Battisti 2016) and landscape composition of connected sweet chestnut forests, wooded chestnut patches, individual chestnut trees and orchards (Medak 2009) in the investigated area. With the host D. kuriphilus present in abundance, successful mate finding and probably no major limiting factors (i.e.…”

Environmental thermal levels affect the phenological relationships between the chestnut gall wasp and its parasitoids

“…The spread of ACGW to Castanea sativa Miller includes all ecosystems where chestnut trees occur (Gilioli et al, 2013), with differential suitability resulting in some areas having better environmental conditions than others (Gil-Tapetado et al, 2018). ACGW affects chestnut production in terms of the yield and economic losses in all of the invaded regions and countries (Battisti et al, 2014;Kos et al, 2015;Tang et al, 2015). The species also represents a perturbation of the natural trophic relationships between the community of native parasitoids and the oak cynipid gall wasps (Askew et al, 2006(Askew et al, , 2013Ferracini et al, 2018).…”

Survey of indigenous parasitoids affecting the invasive chestnut gall wasp Dryocosmus kuriphilus in the Friuli Venezia Giulia region (North‐East Italy)

“…The parasitoids identified belonged to five different Chalcidoidea families (Torymidae, Eupelmidae, Eurytomidae, Pteromalidae and Eulophidae), all of which are associated with D. kuriphilus (Quacchia et al, 2013;Francati et al, 2015;Kos et al, 2015). Among them, Torymidae and Eupelmidae represented approximately 90% of the total hymenopteran parasitoids collected.…”