It was eventually named for N. B. Pierce, who extensively studied the disease. The bacteria, X. fastidiosa , is limited to the xylem or water conducting vessels of plants. Symptoms begin to develop about mid-summer as the bacteria blocks these vessels and a drying or scorching of the leaves is seen. Leaves become chlorotic along the outer edges or adjacent to the dead tissue. The drying or scorching of the leaf continues for a few days to weeks until the leaf eventually falls, usually leaving the petiole attached to the cane.
Petioles gradually die back and fall.
Maturing canes that turn tan will have green islands along the infected portions. When new growth occurs on infected canes it can be delayed and is usually stunted. Leaves on stunted shoots can have a yellow mottling between the major veins. Depending on the variety of grape, death of the entire vine usually occurs in 1 to 5 years. In 1997 a survey was conducted to determine the number of leafhopper species, the size of the populations, and their movements in and around vineyards.