Every research project has a story of who is leading it, and why. For CITRUSBUSTERS, that story starts in Valencia, at the technology centre AINIA. It has now been told in the pages of the magazine of Spain’s largest agricultural association, ASAJA (Asociación Agraria de Jóvenes Agricultores). It recently featured an interview with the two AINIA scientists coordinating the project. In an interview, project coordinators Dr Paloma Juárez Ortega and Dr Kristie Tanner (AINIA) explained, what a Valencian technology centre brings to an eleven-partner consortium, and how citrus growing in the Mediterranean is about to change.

Why the project was created

CITRUSBUSTERS was set up to tackle two diseases that already cost citrus production heavily worldwide. Huanglongbing (HLB), also known as citrus greening, is caused by the bacterium Candidatus Liberibacter and spread by insect vectors. Infected trees show yellow and green mottling on the leaves, produce misshapen and bitter fruit, lose their productivity within a few years, and eventually die. Citrus Black Spot (CBS) is caused by the fungus Phyllosticta citricarpa and leaves dark lesions on leaves and fruits, degrading quality and reducing yield.

The scale of the damage is difficult to overstate. In Brazil, HLB losses exceed 120 million dollars a year. In Florida, HLB damage has averaged more than 1 billion dollars annually over the last five years. Since the disease was detected there in 2005, the cultivated area has shrunk by 30% and production has fallen by 74%, with nearly 5,000 jobs lost every year.

For the Mediterranean, the threat is no longer hypothetical. The HLB vector has already been detected in Europe, and Phyllosticta citricarpa has recently been found on imported fruit from Tunisia and on asymptomatic leaves in Malta, Italy and Portugal.

AINIA plays an essential role

As project coordinator, AINIA leads the planning, execution and reporting of the whole consortium. It also carries several scientific work strands.

AINIA is designing and deploying a sensor-based platform for the early evaluation of crop health, combining hyperspectral, thermal and LiDAR imaging flown from drones. It is working on the in vitro culture and characterisation of Candidatus Liberibacter and Phyllosticta citricarpa. And it is developing biocontrol strategies: specific endolysins against Candidatus Liberibacter, RNA interference tools that silence essential genes in the insect vectors, and bioactive compounds that strengthen the plant’s own immune response.

Coordinating a consortium of eleven organisations from Europe and Brazil, the AINIA scientists explained to ASAJA, is at once a challenge and a strategic opportunity for a Valencian technology centre. It means staying at the forefront of citrus detection, monitoring and biocontrol as an international reference centre, in a moment where these two diseases are moving closer to Mediterranean citriculture every year.

The Strategy

The Brazilian partnership is central to CITRUSBUSTERS, because the country has been dealing with these diseases for years. Working alongside Brazilian researchers gives the consortium access to real-world data on how the diseases spread, how growers try to control them, and how new solutions perform in a landscape where the pathogens and vectors are already present.

CITRUSBUSTERS follows three integrated lines of action.

1. Early detection and outbreak prediction:

Advanced sensors, hyperspectral and LiDAR imaging, co-culture models of pathogens and vectors, and machine-learning algorithms that integrate soil, plant and vector data to anticipate outbreaks before they happen.

2. Plant resistance:

New Genomic Techniques and the extraction of bioactive compounds to strengthen the plant’s natural defences against pathogens and pests.

3. Sustainable biological control:

Encapsulated endolysins targeting Candidatus Liberibacter, antifungal microbial substances against Phyllosticta citricarpa, and RNA interference tools targeted at the insect vector Trioza erytreae.

The Mediterranean citrus industry will look different a decade from now. Systems capable of anticipating outbreaks before they happen. Biocontrol tools and agroecological practices that reduce the reliance on chemical treatments. A shift, decisive but not sudden, from reacting to protecting.

That shift will not happen through any single project. It will happen through cooperation, as well as the exchange of knowledge and the alignment of efforts across the many European and international initiatives now working on complementary lines. Within that wider effort, CITRUSBUSTERS brings its own contribution: eleven partners across Europe and Brazil, working on the detection tools, biological defences and shared knowledge that Mediterranean citriculture will depend on for the decade ahead.

This article is based on the interview with Dr Paloma Juárez Ortega and Dr Kristie Tanner (AINIA) originally published in Spanish in the September 2025 issue of ASAJA’s magazine.