Comparative epidemiology of three tropical whitefly-transmitted geminiviruses

Spatial and temporal patterns of spread of African cassava mosaic, okra leaf curl and tobacco leaf curl viruses in West Africa, East Africa and India share some general characteristics. By comparing the results and running new analyses on available data, it is shown that the epidemiology of these viruses is controlled by the same key variables. For instance, spatial spread is characterised by strong border effects due to accumulation of whitefly vectors (Bemisia tabaci) on the wind-exposed field borders under the influence of the prevailing wind. This results in pronounced environmental gradients of disease. Temporal patterns of virus spread are driven by the sinusoidal fluctuation of temperature over the year which correspond with changes of whitefly populations.