Selected lines of Stylosanthes guianensis, S scabra, S. capitata and S. macrocephala were established at field sites at Planaltina and Campo Grande in Brazil and at Carimagua and Caquetá in Colombia. Weather conditions at each site were monitored continuously using an automatic weather station. Data on anthracnose severity caused by Colletotrichum gloeosporioides were collected by visually assessing these lines at monthly intervals and analysed to study disease progress on susceptible and resistant lines in relation to weather