Spatial Distribution of Symptomatic Grapevines with Esca Disease in the Madrid Region (Spain)

Abstract

From 1998 to 2001 three vineyards in the three areas Arganda, San Martin de Valdeiglesias and Navalcarnero, included in the vine-growing region “Wines of Madrid”, were surveyed for esca incidence and spatial distribution of infected vines. Individual vines were recorded as “diseased” when they showed esca symptoms, both in summer surveys (symptoms on leaves, weak growth, short branches growth) and in winter surveys (necrosis of trunk and main branches). Data recorded over several years in the same vineyard and data from different vineyards in the same year were compared in order to study disease spread and possible primary sources of infection. Our results showed that: i) esca foliar symptoms were discontinuous from year to year; ii) the distribution of infected vines in the vineyard was random and, iii) the disease was not spread between adjacent vines.