initially small, brown to black
oval lesions with a typical bullsí
eye appearance of concentric rings on leaves, stems and petioles.
as disease progresses, lesions become necrotic, usually surrounded
by a wide yellow halo.
soon after, the whole leaf blade turns
and drops. Blackened veins are observed on the lower side or undersurface
of the leaf.
lesions on petioles and stems are initially grey then turn black
and sunken as they enlarge. Petioles and stems are girdled
and the plant dies.
lesions get a silvery tone during dry conditions.
bases and middle sections are more affected than the vine
terminals. The ground under affected vines is often carpeted with
blackened leaf debris.