1 Initial speck stage: faint, minute, reddish-brown specks on the lower surface of the leaf. Third or mature spot stage: the centres of the lesions dry out becoming light grey or buff coloured and a bright yellow transitional zone appears between them and the normal green colour of the leaf. The lesions remain clearly visible after the leaf has collapsed or withered because of their light coloured centre and dark border. 6 3 Second-streak stage: streaks change colour from reddish brown to dark brown or black, sometimes with a purplish tinge, clearly visible at the upper surface of the leaf. First streak stage: specks elongate, becoming slightly wider to form narrow reddish-brown streaks. 2 entity First-spot stage: the streaks broaden and become more or less fusiform or elliptical in outline and a water soaked border appears around each lesion. 4 scale_of 5 Second-spot stage: the dark brown or black centre of each lesion becomes slightly depressed and water soaked border becomes more pronounced. attribute acronym method_of variable_of Meredith and Lawrence (1969) - condensed