Abstract
Observation and the symptomatology of the disease enabled the author to demonstrate that the appearance of the symptoms and their general characteristics could be classified into types varying with the period of growth of the plant. For instance, systemic symptoms were observed in the beginning (type I ) or in the middle of the period of growth (type II ) . Compared with types A, B and C reported by Palm, types A and B corresponded to type I described by the author, while in type C there were no systemic symptoms but only small streaks developed in the beginning of the infection. The author also discussed the relationship between the stage of growth and the symptomatology, adding type II to Palm's classification.
It was also shown that as far as the growth progression of maize was concerned, the emergence of leaves was advanced by 1 to 2 days in humid tropical areas. This precocity was the main reason why prevention of the disease by the use of drugs was made difficult. The need for fungicides able to penetrate into the plant so as to curb the growth of hyphae infecting it was further discussed.
