Comparing patterns and scales of plant virus phylogeography: in Madagascar and in continental Africa.

(RYMV) in Madagascar Island provides an opportunity to study the spread of a plant virus disease after a relatively recent introduction in a large and isolated country with a heterogeneous host landscape ecology. Here, we take advantage of field survey data on the occurrence of RYMV disease throughout Madagascar dating back to the 1970s, and of virus genetic data from ninety-four isolates collected since 1989 in most regions of the country to reconstruct the epidemic history. We find that the Malagasy isolates belong to a unique recombinant strain that most likely entered Madagascar through a long-distance introduction from the most eastern part of mainland Africa.

Bark essential oil of Cedrelopsis grevei from Madagascar: investigation of steam-distillation conditions.

The effect of the distillation time on the yield and chemical composition of the bark essential oil of Cedrelopsis grevei Baill. was investigated. Distillation kinetics were determined for three batches of bark sampled from two sites, i.

Rice yellow mottle virus in Madagascar and in the Zanzibar Archipelago; island systems and evolutionary time scale to study virus emergence.

Rice yellow mottle virus (RYMV), of the genus Sobemovirus, is a major threat to rice cultivation in Africa. Long range transmission of RYMV, difficult to study experimentally, is inferred from a detailed analysis of the molecular diversity of the virus in Madagascar and in the Zanzibar Archipelago (Zanzibar and Pemba Islands; Tanzania) compared with that found elsewhere in Africa. A unique successful introduction of RYMV to Madagascar, which is ca.