Title: Reproductive traits and assessment of the non-target impacts
of Torymus sinensis, biocontrol agent of the Asian chestnut gall
wasp
Author(s): Ferracini, Chiara1, Ferrari, Ester1, Pontini, Marianna1,
Picciau, Luca1,Alma, Alberto1
Affiliation of author(s): 1Dipartimento di Scienze Agrarie, Forestali e
Alimentari (DISAFA), ULF Entomologia Generale e Applicata, University of Torino, largo P. Braccini 2, 10095 Grugliasco (TO), Italy
Corresponding author: Ferracini, Chiara; E-mail: chiara.ferracini@unito.it
Keywords (up to six): Torymus sinensis, diapause, non-target effects, hybridization, classical biological control, risk assessment
Abstract:
The European chestnut (Castanea sativa L.) has been significantly impacted by the invasion of the Asian chestnut gallwasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), considered as one of the most recent examples of exotic pests accidentally introduced in the European forestry environment. This pest was successfully controlled in Italy with the introduction of the parasitoid Torymus sinensis Kamijo (Hymenoptera: Torymidae) from Japan, and the release in infested chestnut orchards and coppices.
A in-depth post-release study was performed to improve knowledge about the reproductive traits of this biocontrol agent, and to assess its potential environmental impact on native non-target species, such as host-range expansion and hybridization.
Investigations highlighted that T. sinensis is a synovigenic parasitoid, able to undergo extended diapause mainly as late instar larva. Furthermore, field evidence for movement of the parasitoid to native
oak galls was reported, even if with minimal impact, while hybridization with native Torymus species both in field and laboratory conditions was never observed.
