In spring, small dark spots (about 1mm in diameter) surrounded by yellow halos develop on the leaves (Figures 1).
The older, lower leaves are the first to show symptoms. Severely infected leaves may experience premature leaf fall.
On canes and shoots the symptoms are often restricted to the lower internodes. Small dark spots develop on the cane or shoot and with the growth of the shoot these spots expand and elongate to form black lesions 3-6mm in length (Figures 3 and 4).
These lesions may coalesce to form large scabby areas (Figure 5). The lesions may girdle the shoots as they mature or cause the shoots to become stunted and die. If infection spreads into the rachis, the young bunches may dry out and fall off.
Fruit infection can occur, the berries developing brown spots which enlarge and darken as the disease progresses. The berries may become mummified and fall from the bunch. Fruit infection is rare in Australia.
The disease overwinters as small fruiting bodies on canes and other woody tissue (spurs and prunings), that can often appear bleached with small dark spots. Phomopsis viticola has also been associated with vine decline and grapevine cankers overseas.