Main symptoms

• Leaves

The first symptoms of Pierce's disease are foliar and appear especially during hot, dry summer periods, or when vines are under water stress. Thus, russeting and partial drying out of the leaves occur. The lesions of the limbus in green are sectorial and / or peripheral, brownish in color, yellow to reddish on the border. The withering of the leaf blade gradually spreads, and subsequently entire leaves necrotize and drop, only the petioles remaining attached. 

• Twigs

The affected twigs grow irregularly, remaining green in places. In the following seasons, the affected vines bud later and produce chlorotic and stunted shoots. They rarely survive for more than one to two years.

( symptoms observed on other plant species: EPPO )