Evaluation of sugarcane mosaic incidence in Florida.
A survey of sugarcane mosaic [?sugarcane mosaic virus] was conducted in Florida, USA, to determine the extent of its spread from an outbreak that was first observed in 1996. Incidence of mosaic was determined based on serological detection in leaves collected randomly from plants in commercial sugarcane fields. Incidence of mosaic in sugarcane cv. CP 72-2086 ranged from 0 to 97% in growers' fields in Florida. The highest incidence of mosaic in grower fields was located 10-15 km east of Pahokee. Adjacent fields and fields in adjacent surveying sections had large differences in incidence of mosaic on CP 72-2086 with the source of seedcane as a probable reason for the range of infection. Multiple cultivars were susceptible to mosaic infection in a natural spread experiment. However, these cultivars had lower incidences of mosaic than CP 72-2086 in fields located in an area of high mosaic infection and were not infected in a second spread experiment planted the following year in the same general area. Although CP 72-2086 was susceptible to infection, no losses in biomass or sugar were observed in either the plant or first ratoon crops in a 2-year-yield test. Thus, the cultivar, CP 72-2086, is considered tolerant to mosaic. The results suggest that planting of mosaic-free seedcane will lower the incidence of mosaic in the area.