What agroecological alternatives are there to combat Huanglongbing in the Caribbean?

The Citrus Evolutionary Structure, Polyploidy and Genetic Improvement (in French: SEAPAG) team at Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD - Centre for International Cooperation in Agricultural Research for Development) is proposing agroecological alternatives for combating Huanglongbing disease (HLB) in the Caribbean. Trials focusing on HLB tolerance have been set up mainly in Martinique and Guadeloupe, where our research stations are based. Expansion throughout the Caribbean is underway. Indeed, all the Caribbean producer countries have seen their production fall sharply. Our research and development work is divided into different timeframes for obtaining results, within a framework of sustainable agriculture. In the short-term, we select individuals from local populations who are then conserved, protected, characterised and observed for their tolerance to HLB, as well as their organoleptic qualities. These heritage plots at CIRAD in Martinique and Guadeloupe are veritable conservatories of original and promising trees. This conservation measure is recommended during our Caribbean exchange missions, so that other territories can adopt this principle of protection. As another rapid alternative, CIRAD has developed and tested a technical itinerary, with details on fertilisation and tree pruning, to combat HLB and prolong the life of trees in the face of this serious disease. With the aim of improving cultivars in the medium and long-term, we are working in direct collaboration with the INRAE (Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement - French National Research Institute for Agriculture, Food and the Environment) CIRAD Biological Resources Centre in Corsica (France), which has a collection of over 1,200 accessions, to obtain and select rootstocks and cultivars such as a remontant lime or high-performance mandarin hybrids that are adapted to conditions in the West Indies and, above all, tolerant, or even resistant, to HLB. We now have populations of hundreds of trees, which are currently being evaluated in Martinique and Guadeloupe, as well as in other Caribbean countries such as Jamaica and Cuba.