First detection and epidemiology of Candidatus Liberibacter asiaticus associated with Huanglongbing in Martinique and Guadeloupe, French West Indies : Poster 07

Huanglongbing is an unculturable vascular citrus pathogen transmitted from infected to healthy plants through grafting or by citrus psyllids Diaphorina citri, mainly in Asia and America; and Trioza erytreae in Africa. This phloem limited Gram-negative bacterium causes dramatic yield Joss and is associated with three different species (2): (i) Candidatus Liberibacter asiaticus (Las), the most epidemiologically active; (ii) Ca. L. ajricanus (Laf), only found in Africa; and (ii i) the newly described Ca. L. americanus (Lam), which appeared in 2005 in Brazil (3). Earliest symptoms appear on young shoots, reaching rootstock and spreading by sector on the tree. Infection triggers starch accumulation in the leaf cells and disruption of the chloroplasts, causing leaf mottling. Movement of sucrose From the leaves to the fruit through the phloem is disrupted and leading to fruit starvation, and triggers small lopsided fruits having a bitter and acidic flavor as well as premature fruit drop. Considered as a quarantine organism in America and Europe, Las is actively affecting North America and Asia, and research is leading towards psyllid management and resistance breeding. Despite the fact that Reunion Island has successfully controlled Las by introducing a psyllid parasitoid Tamarixia radia/a ( 1), this was significantly less effective or reproducible within other territories. First detection of Las occurred in 20 12 in Guadeloupe and 2013 in Martinique, affecting various Citrus spp. belonging to the Rulaceae family. Official method has been set up to give real detection capabilities to local National Plant Protection Organizations that have built a solid detection survey. Interaction between ail the official organizations allowed managing an epidemic situation within short lime framework. We report here detection scheme, official method and territory surveillance strategies to detect and constrain Candidatus Liberibacter asiaticus in Martinique and Guadeloupe. (Texte intégral