The European Tropicsafe project has demonstrated the efficacy of a parasitoid in reducing the spread and abundance of one of the insect vectors of HLB disease, the African psyllid Trioza erytreae.
The vector was first located on the European continent in Pontevedra in 2014 but the disease has not yet been detected. Despite this, the sector makes constant efforts to find an answer against it before the first contagion occurs. In 2015, the insect was detected in the north of Portugal. Since then, it has been colonizing the Portuguese Atlantic coast. In 2017 it was located in the Lisbon Region and the Tagus Valley, where it remained until last October when it was detected in the Algarve Region.
With the help of the Valencian Institute of Agrarian Research (IVIA), researchers identified that the Tamarixia dryi wasp from South Africa is an effective parasitoid against Trioza erytreae. Later, its suitability was verified in collaboration with the Canarian Institute of Agricultural Research, and in 2019 the IVIA transferred the study to Galicia for the breeding and release of this biological control organism. This phase included its production in the Maceda nursery and the monitoring of Tragsa and Tragsatec as commissioned by the Plant Health Service. The latest data confirms that this was the right approach.
The small South African wasp adapt to the Iberian Peninsula's climate and managed to decimate the transmission vector without unwanted impacts. In the spring outbreaks of 2020, the rate of parasites ranged from 7.6 to 38.9% in the three chosen localities. In the summer of 2021, the density of the psyllid had dropped so much that it was impossible to carry out these calculations, stated representatives of the Tropicsafe project.
After this experience, Tropicsafe is already working in other infested areas of the Iberian Peninsula, controlling the vector insect before it can make the leap to citrus-producing areas, where the vector lacks natural barriers. With no cure on the horizon, HLB disease is a latent threat to citrus around the world.
The Tropicsafe project is financed through the European Union's Horizon 2020 program. The project has 22 partners from 12 countries, including the Spanish Fundación Empresa-Universidad Gallega (FEUGA), the Valencian Institute for Agrarian Research (IVIA), and the University of Bologna, which is leading the project.