Frogeye leaf spot, caused by the fungus Cercospora
sojina Hara, is a worldwide important soybean disease,
causing both yield losses and seed deterioration. The use
of resistant cultivars is the most efficient and costeffective
means of controlling this disease, but the existence
of several C. sojina races (Yorinori, 1989b) demands
the permanent search for new sources of resistance
and their incorporation into resistance breeding programs.
Another factor to be considered is that the evaluation of
soybean crops with regard to this disease is a timeconsuming
process, which requires expertise for the precise
distinction between susceptible and resistant plants.