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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #434869

Research Project: Understanding and Managing the Trunk Disease Esca

Location: Crops Pathology and Genetics Research

Project Number: 2032-21220-007-11-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Apr 15, 2018
End Date: Apr 15, 2019

1) Evaluate vine surgery to manage Esca in an infected vineyard. 2) Identify Esca pathogens, with a focus on Basidiomycete wood-rotting fungi.

For Objective 1, our approach is to perform vine surgery on vines with moderate symptoms of Esca. At the time we cut them at the base of the trunk, we will see if wood symptoms of Esca pathogens are present. After retraining the vines, we will monitor them for leaf symptoms. Our hypothesis is that vines without the internal wood symptoms (black streaking for Ascomycetes, white rot for Basidiomycetes) will have a low frequency of infection at the base of the trunk (culture attempts will confirm) and, thus, will mostly benefit from vine surgery. Vines with wood symptoms at the base of the trunk, however, will be more likely to eventually develop Esca symptoms because the sucker trained into a new trunk (and vine) will likely have been infected. For Objective 2, we plan to sample vineyards ages 10 to 15-years-old within Fresno, San Luis Obispo, San Joaquin, and Sonoma Counties (10 per county), which were selected based on the following criteria: under-sampled in previous studies for the Esca pathogens, representative of distinct regions/ climates, or counties from which we received reports of apoplexy in 2017. Isolates will be identified based on morphological and molecular assays. The pathogenicity of representative isolates of each Basidiomycete species will be tested by inoculation in the greenhouse to potted grapevines.