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The grapevine trunk-disease complex limits vineyard longevity in all major grape-growing regions. Although trunk diseases have been distinguished based on etiologies (e.g., Botryosphaeria-, Eutypa-, and Phomopsis dieback, Esca) and causal agents, mixed infections of trunk pathogens and other wood-colonizing fungi are frequent in grapevines. These diverse fungal communities in grapevine span four classes in the Pezizomycotina (Ascomycota) and 10 genera in the Hymenochaetales (Basidiomycota). Traditional identification based on morphology is largely untenable because of overlap in colony characteristics or spore dimensions, or lack of sporulation in culture. When based on DNA sequencing, searches of uncurated, public molecular databases can lead to misidentifications. The new molecular database TrunkDiseaseID.org is populated with accurate rDNA ITS sequences from 250 + isolates (pathogens and saprobes) and secondary DNA barcodes for delineating closely related species. Currently, no such comprehensive database exists for grapevine wood-colonizing fungi. In addition to ITS and secondary barcode sequences, this database provides a scientific reference, origin, and ecological status for each isolate, to aid diagnosticians in communicating results and recommendations to growers. Outreach through the National Plant Diagnostic Network and the US Department of Agriculture's Identification Technology Program will connect diagnosticians to this new database for grape. [ABSTRACT FROM AUTHOR]

Grapevine wood hosts diverse fungal species, including pathogens that cause grapevine trunk diseases and wood decomposers, with detrimental effects on yields. This study focuses on the effects of two pruning systems, minimal (min-) or spur-pruning, on the community of trunk pathogens and other wood-colonizing fungi in the trunks of two cultivars, Mourvèdre and Syrah. Culture and DNA-based methods were used to describe the fungal communities. In both cultivars, especially Syrah, spur-pruned vines had more wood necrosis than min-pruned vines, and the community of spur-pruned Syrah was distinguished by its single-stranded conformational polymorphism (SSCP) profile. Diversity profiles of all 88 cultivated taxa and canonical correspondence analyses of the 15 most frequently isolated taxa revealed differences in community structure due to pruning system, trunk location, and/or wood type. Greater levels of wood necrosis may be due to the composition of the fungal community rather than to a greater diversity of taxa. [ABSTRACT FROM AUTHOR]

Cadophora species are reported from grapevine ( Vitis vinifera L.) in California, South Africa, Spain, Uruguay, and Canada. Frequent isolation from vines co-infected with the Esca pathogens ( Togninia minima and Phaeomoniella chlamydospora ), and confirmation of its ability to cause wood lesions/discoloration in pathogenicity tests, suggest that C. luteo-olivacea is part of the trunk pathogen complex. In North America, little is known regarding the diversity, geographic distribution, and roles of Cadophora species as trunk pathogens. Accordingly, we characterized 37 Cadophora isolates from ten US states and two Canadian provinces, based on molecular and morphological comparisons, and pathogenicity. Phylogenetic analysis of three loci (ITS, translation elongation factor 1-alpha (TEF1-α) and beta-tubulin (BT)) distinguished two known species ( C. luteo-olivacea and Cadophora melinii ) and three newly-described species ( Cadophora orientoamericana , Cadophora novi-eboraci , and Cadophora spadicis ). C. orientoamericana , C. novi-eboraci , and C. spadicis were restricted to the northeastern US, whereas C. luteo-olivacea was only recovered from California. C. melinii was present in California and Ontario, Canada. Morphological characterization was less informative, due to significant overlap in dimensions of conidia, hyphae, conidiophores, and conidiogenous cells. Pathogenicity tests confirmed the presence of wood lesions after 24 m, suggesting that Cadophora species may have a role as grapevine trunk pathogens. [ABSTRACT FROM AUTHOR]