Classical biological control of Trioza erytreae in the EPPO region
Trioza erytreae (Hemiptera: Triozidae – EPPO A2 List, vector of huanglongbing) is a pest of citrus and was first recorded in the EPPO region in 1994. Tamarixia dryi (Hymenoptera: Eulophidae) has been utilised as a classical biological control agent against T. erytreae in the Reunion Island in the 1970s. As part of the TROPICSAFE EU funded project, research was undertaken on the potential to use T. dryi in Europe. The aims were (1) identify the parasitoid complex of T. erytreae in South Africa, (2) evaluate the specificity of the biocontrol agent T. dryi and (3) determine the establishment, dispersal, and impact of T. dryi on T. erytreae in Spain. Surveys in South Africa also found Psyllaephagus pulvinatus and an unidentified new species of Tamarixia. In the Canary Islands, host range testing was conducted using 11 species of alternative psyllids selected according to their phylogenetic relatedness to T. erytreae. Results showed that T. dryi only attacks T. erytreae. The parasitoid was released in spring in Tenerife in 2018 and its spread was measured in 2019 and 2020. It was originally released in the north of the island and 6 months later it had spread throughout the island. It was also found in other Canary Islands. In Tenerife, Gran Canaria, and La Palma, the proportion of orchards with T. erytreae had significantly reduced, highlighting an impact of the biocontrol agent. In mainland Spain, the parasitoid was released in Galicia in 2019 and 2020, and within 6 months it has spread more than 20 km from the point of release. 18 months later and with more than 45 releases, it had spread widely. In Pontevedra, A. Coruna and Lugo, significant decreases in the proportion of orchards infested with T. erytreae was shown. T. dryi may be considered for inclusion into EPPO Standard PM 6/3 Biological control agents safely used in the EPPO region, Appendix II Successful established classical biological control agents, once it fulfils the criteria (i.e. found at least 5 years after release to be successfully established in part of the EPPO region without reports of adverse effects).
Sources
TROPICSAFE project website (2022): https://www.tropicsafe.eu/
Pérez-Rodríguez J, Krüger K, Pérez-Hedo M, Ruiz-Rivero O, Urbaneja A, Tena A (2019) Classical biological control of the African citrus psyllid Trioza erytreae, a major threat to the European citrus industry. Scientific Reports 9, 9440. https://doi.org/10.1038/s41598-019-45294-w
Urbaneja-Bernat P, Pérez-Rodríguez J, Krüger K, Catalán J, Rizza R, Hernández-Suárez E, Urbaneja A, Tena A (2019) Host range testing of Tamarixia dryi (Hymenoptera: Eulophidae) sourced from South Africa for classical biological control of Trioza erytreae (Hemiptera: Psyllidae) in Europe. Biological Control 135, 110-116