APS Abstracts of Presentations

Susceptibility of grapevine pruning wounds to infection by Phaeomoniella chlamydospora and Phaeoacremonium spp. W. D. GUBLER, A. Eskalen, S. N. Rooney, A. J. Feliciano, and A. Khan. Dept of Plant Pathology, UC Davis, CA. Phytopathology 92:S32. Publication no. P-2002-0231-AMA.

Spores of Pa. chlamydospora (Pc), Phaeoacremonium aleophilum (Pa) and Pm inflatipes (Pi) were shown to be aerially disseminated from pycnidia and unknown sources, respectively in CA vineyards. These pathogens are responsible for causing black measles (esca) and Petri disease. Petri disease is a disease of 1-5 yr-old grapevines and black measles, which is a disease of older grapevines has in recent years become more prevalent on young grapevines in CA. Spore release occurred with rainfall events during the late winter and spring when pruning was done. Pa. chlamydospora, Pm inflatipes and Pm. aleophilum were capable of penetrating 1-day-old to 120-day-old pruning wounds. Susceptibility was highest in fresh wounds and decreased with age of the pruning wound. In Thompson Seedless and Cabernet Sauvignon, vascular streaking moved down to the bud positions below the pruning wound thus effecting new shoot positions. Symptoms occurred as dark vascular streaking and stunted shoot growth having foliar symptoms similar to those of black measles.

Copyright 2002 by The American Phytopathological Society. All rights reserved.