Occurrence of Hyphae of Uncinula necator in Buds of Grapevine. R. C. Pearson, Associate Professor, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. W. Gärtel, Professor, Biologische Bundesanstalt für Land-und Forstwirtschaft, Institut für Pflanzenschutz im Weinbau, Bernkastel-Kues, Federal Republic of Germany. Plant Dis. 69:149-151. Accepted for publication 3 August 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-149.

Hyphae of Uncinula necator were found inside buds of grapevine cultivar Trollinger by scanning electron microscopy. Hyphae 3–4 μm in diameter with characteristic lobate appressoria were observed on the adaxial surfaces of prophylls (bud scales) dissected from the interiors of green buds on infected shoots. Green shoots with primary powdery mildew (flag shoots) were found most frequently at node positions 3–5 on 1-yr-old canes.

Keyword(s): Oidium, Vitis vinifera.