Huanglongbing (HLB), also known as “greening”, has become the greatest phytosanitary threat to global citrus production and keeps producers, scientists and agricultural authorities in Europe on alert. The disease, caused by bacteria transmitted by insect vectors, has no known cure and has already caused serious economic losses in large producing regions such as Florida and Brazil.
According to data from the United States Department of Agriculture and the University of Florida, citrus production in the North American state fell by nearly 80% in the last two decades due to the impact of HLB, combined with extreme climate phenomena. Florida went from producing more than 240 million boxes of oranges in the early 2000s to fewer than 20 million in recent seasons.
The disease causes deformation and premature fall of the fruits, loss of quality and progressive weakening of the trees until production becomes unviable. In Brazil, the world’s largest exporter of orange juice, the advance of HLB forced the uprooting of millions of trees and strengthening phytosanitary controls in states such as São Paulo and Paraná.
Faced with this scenario, Florida developed mitigation strategies based on intensive nutrition, high-frequency irrigation systems, biological control of insects and genetic improvement to obtain more tolerant varieties. Researchers from the University of Florida are also working on biotechnological tools aimed at prolonging the useful life of plantations and reducing the economic impact of the pathogen.
Spain, the main citrus producer in the European Union, is keeping HLB out of its commercial crops for now, although authorities consider the risk of introduction to be high due to the expansion of the insect vector and the international trade in plant material.
The Ministry of Agriculture, Fisheries and Food and the autonomous communities reinforced surveillance, inspection and phytosanitary control protocols, especially in the Valencian Community, the main Spanish citrus region. Monitoring programs for the insect Trioza erytreae, detected in northern areas of the peninsula, were also intensified.
In this context, the UPV recently brought together international experts in Valencia to analyze prevention and adaptation strategies.
The director of the Mediterranean Irrigation and Agrosystems Research Center (CIRAM) and professor at the UPV, Alberto San Bautista Primo, told La Razón that “the day was an extraordinary opportunity to learn first-hand about the strategies that were being developed and the lines of research that could help anticipate efficient agronomic responses.”
The event also served to reinforce collaboration between universities, companies, public administration and agricultural organizations.
“University research must be closely connected to the real needs of the agri-food sector to generate transferable knowledge, aimed at improving productivity, innovation and agronomic management of Mediterranean agri-food systems,” highlighted San Bautista Primo.
Current lines of research focus on resistant varieties, precision agronomic management, genetic improvement and new early detection technologies. For specialists, international cooperation will be key to prevent Europe from facing a citrus crisis similar to that experienced in Florida and Brazil.