Spatial patterns of grapevines with Eutypa dieback in vineyards with or without perithecia

• Published in: Phytopathology Vol. 83; no. 12; pp. 1440 - 1448
• Main Authors: Munkvold, G.P, Duthie, J.A, Marois, J.J
• Format: Journal Article Conference Proceeding
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01-12-1993
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; CALIFORNIA; CALIFORNIE; ENCUESTAS SANITARIAS; ENQUETE PATHOLOGIQUE; EUTYPA ARMENIACAE; FACTEUR DU MILIEU; FACTORES AMBIENTALES; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; PODER PATOGENO; POUVOIR PATHOGENE; SINTOMAS; SYMPTOME; VARIACION GENETICA; VARIATION GENETIQUE; VARIEDADES; VARIETE; VIGNOBLE; VINA; VITIS; California; United States; North America; America; Cultivated field; Plant pathogen; Mycosis; Vitis; Biomathematics; Epidemiology; Statistical study; Dispersion; Viticulture; Diagram; Fungi; Infection; Spatial distribution; Biodynamics; Perithecia; Applied mathematics; Fruit crop; Vitidaceae; Dicotyledones; Angiospermae; Ascomycetes; Spermatophyta; Thallophyta; Inoculum
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/Phyto-83-1440

Eight vineyards in northern and central California were surveyed during three consecutive years, 1989-1991, and the presence or absence of Eutypa dieback symptoms was recorded for each vine in contiguous blocks of 1,250-3,150 vines. The vineyards were located in areas with different levels of mean annual rainfall; some vineyards contained inoculum sources (perithecia) of Eutypa lata; others did not. The spatial patterns of infected vines were examined by ordinary runs, two-dimensional distance class, spatial autocorrelation, and geostatistical analyses. Disease incidence ranged from 3.4% in 1989 to 81.5% in 1991. During the study, disease incidence more than doubled in five of the vineyards. Vineyards with perithecia had higher disease incidence. A disease gradient or edge effect was detected in two vineyards that did not contain inoculum sources; one of these was found to be adjacent to a vineyard with E. lata perithecia. The different analyses consistently described the relative randomness of the patterns of diseased vines among the vineyards. Those vineyards that contained perithecia had a higher proportion of vineyard rows with nonrandom disease patterns according to runs analysis. Two-dimensional distance class analysis showed that vineyards with perithecia contained clusters of diseased vines or other nonrandom patterns. Vineyards with perithecia also consistently had more significant spatial autocorrelation coefficients and semivariograms that indicated spatial dependence at distances up to 25 m. A nonrandom pattern was consistently found in one vineyard that was not near any known inoculum source. Three other vineyards with no known inoculum sources nearby were consistently considered to have random patterns, according to the spatial pattern analyses. In these vineyards, there was no evidence that would indicate disease spread by means other than airborne ascospores from distant sources