Résumé
Sugar cane yellow leaf virus (SCYLV), the causal agent of an emerging aphid vectored disease called yellow leaf, is present in numerous sugar cane countries world wide. In the Caribbean, the virus was first identified in the French West Indies in 1996. SCYLV was diagnosed later on in CIRAD's sugar cane quarantine in Montpellier in seed cane originating from Barbados and Cuba. It was also detected in Belize lately. Recent studies showed that genetic variationoccurs within SCYLV, and four genotypes of the virus differing in aggressivity and virulence were reported. Determination of SCYLV genotypes occurring in a sugar cane growing location and characterization of vector population dynamics are essential to analyse the risk of yellow leaf epidemics. Yellow leaf incidence in 34 farmers¿ fields, aphid vector populations and distribution of SCYLV genotypes were determined in two closely related islands, Guadeloupe and Martinique. Large differences in disease incidence and frequency of virus genotypes between the two locations suggested the occurrence of strong local effects or interactions that need to be determined. Therefore, disease progress in one location may so far not be predicted based on the situation in another relatively close location, and the status of yellow leaf disease must be studied locally to determine the risk of yellow leaf epidemics and impact on sugar cane production. (Résumé d'auteur)