The fungus overwinters probably by sclerotia laid down initially in late summer or autumn as host tissues harden, and may remain viable for 3-5 years. The fungus remains inactive within affected grapevine canes, and as spores on the surface of infected berries which have fallen to the ground. Sclerotia form on the shoots, over-winter and provide inoculum in spring. Sporulation in spring is favoured by wet, humid weather, however, it may occur at temperatures as low as 2 C. Masses of spores are released and are splashed into the opening buds, leaves, shoots and fruit where infection occurs.
Young tissues are highly susceptible.
Secondary invasion via conidial infection of young shoots occurs during the growing season. Anthracnose lesions of leaves are ususally circular with dark brown margins, pale centres and surrounded by a light green halo. Diseased plants may exhibit stunting and death of young shoots, deterioration of older shoots and stocks and loss of fruit yield. Loss of young bunches, and distortion, splitting, mummification or abscission of berries may also occur. Identification Lesions caused by E. ampelina on leaves, stems and fruits are usually circular, and may be distinct or joined together.