Grape

No known vector.

No specific signs are present.

Lesions on leaves are initially yellow on white cultivars and bright red to rddish brown on red cultivars. A reddish brown necrosis develops in the center of the lesion, leaving only a thin margin of yellow or red tissue between the necrotic and green areas of the leaf. The lesions are typically confined to the major veins and the edge of the leaf and are several cm wide. Early infections occur on the first to the sixth leaf position of young shoots, resulting in minor losses. Later infections attack leaves up to the 10th or 12th position on the shoot, which results in severe defoliation. The fungus also attacks the inflorescences and berries, causing them to rot and dry out.

Young leaves are susceptible after they reach a width of about 5 cm (2 in.), but the probability of infections increases from the 6-leaf stage. After an incubation period of two to four weeks, the fungus invades the vascular elements of infected leaves, causing symptom development (Konig et. al., 2009).

Morphological: The diagnostic feature of the fungus is the presence of sine-wave pattern of hyphae observed in the xylem vessel elements when affected plant tissues are cleared by boiling in 2% aqueous potassium hydroxide for 2-3 min (Plant Health Australia, 2004).

Pseudopezicula tetraspora is a four-spored American species. Unlike other members of Peziculoideae which attack woody stems and branches, these species occur on leaves, mostly in association with the vascular elements