Identification of Torymus sinensis and T. beneficus (Hymenoptera: Torymidae), introduced and indigenous parasitoids of the chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae), using the ribosomal ITS2 region

2006 ◽  
Vol 36 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Kaori Yara
2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Ambra Viviani ◽  
Rodolfo Bernardi ◽  
Andrea Cavallini ◽  
Elisabetta Rossi

Abstract Torymus sinensis Kamijo (Hymenoptera: Torymidae) is an alien parasitoid that is used in many areas of the world for biological control the Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae). In Italy, this parasitoid was imported from Japan in 2003 and subsequently multiplied and released throughout the country. In this study, a phylogenetic investigation was carried out on insects from three different sites in northern Tuscany (Italy). Moreover, the possible hybridization between T. sinensis and some native Torymus species was evaluated. The conserved region 18S rRNA gene and the hypervariable ITS2 (Internal Transcribed Spacer 2) region of the ribosomal cistrone were selected as molecular markers. Sequencing the amplified products, after cloning, ruled out any hybridization between T. sinensis and the native Torymus species, and also confirmed the presence of two haplotypes for the Tuscan population of T. sinensis both for the region of the 18S rRNA gene as well as for the ITS2 region. These results confirm that the environmental impact of the alien parasitoid T. sinensis in the study site is acceptable, although an extensive and repeated monitoring would be desirable.


Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 86
Author(s):  
Xiaohui Yang ◽  
Yu Hui ◽  
Daohong Zhu ◽  
Yang Zeng ◽  
Lvquan Zhao ◽  
...  

Dryocosmus kuriphilus (Hymenoptera: Cynipidae) induces galls on chestnut trees, which results in massive yield losses worldwide. Torymus sinensis (Hymenoptera: Torymidae) is a host-specific parasitoid that phenologically synchronizes with D. kuriphilus. Bacteria play important roles in the life cycle of galling insects. The aim of this research is to investigate the bacterial communities and predominant bacteria of D. kuriphilus, T. sinensis, D. kuriphilus galls and the galled twigs of Castanea mollissima. We sequenced the V5–V7 region of the bacterial 16S ribosomal RNA in D. kuriphilus, T. sinensis, D. kuriphilus galls and galled twigs using high-throughput sequencing for the first time. We provide the first evidence that D. kuriphilus shares most bacterial species with T. sinensis, D. kuriphilus galls and galled twigs. The predominant bacteria of D. kuriphilus are Serratia sp. and Pseudomonas sp. Furthermore, the bacterial community structures of D. kuriphilus and T. sinensis clearly differ from those of the other groups. Many species of the Serratia and Pseudomonas genera are plant pathogenic bacteria, and we suggest that D. kuriphilus may be a potential vector of plant pathogens. Furthermore, a total of 111 bacteria are common to D. kuriphilus adults, T. sinensis, D. kuriphilus galls and galled twigs, and we suggest that the bacteria may transmit horizontally among D. kuriphilus, T. sinensis, D. kuriphilus galls and galled twigs on the basis of their ecological associations.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Tiziana Panzavolta ◽  
Francesco Croci ◽  
Matteo Bracalini ◽  
George Melika ◽  
Stefano Benedettelli ◽  
...  

Native parasitoids may play an important role in biological control. They may either support or hinder the effectiveness of introduced nonnative parasitoids released for pest control purposes. Results of a three-year survey (2011–2013) of the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) populations and on parasitism rates by native indigenous parasitoids (a complex of chalcidoid hymenopterans) in Italian chestnut forests are given. Changes in D. kuriphilus gall size and phenology were observed through the three years of study. A total of 13 species of native parasitoids were recorded, accounting for fluctuating parasitism rates. This variability in parasitism rates over the three years was mainly due to the effect of Torymus flavipes (Walker) (Hymenoptera: Torymidae), which in 2011 accounted for 75% of all parasitoid specimens yet decreased drastically in the following years. This strong fluctuation may be related to climatic conditions. Besides, our data verified that parasitoids do not choose host galls based on their size, though when they do parasitize smaller ones, they exploit them better. Consequently, ACGWs have higher chances of surviving parasitism if they are inside larger galls.


2020 ◽  
Vol 156 (2) ◽  
pp. 111-116
Author(s):  
M.T. Jennings ◽  
R.R. Askew

The invasive chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) is a major pest species of Castanea spp. worldwide. It only arrived in Britain in 2015 and the parasitoid community associated with it was studied in 2019. Eight native species of chalcidoid, previously known to be associated with oak gall wasps, were identified. These results are compared to a similar study (2016–2019) in France where four parasitoids were reared. However, this community included the deliberately introduced Torymus sinensis Kamijo, a specific biological control agent of D. kuriphilus. The presence of T. sinensis and the differences between the two communities is discussed.


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