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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Research Project #437187

Research Project: Novel Field-Based Diagnostic Strategies for Management of Powdery Mildew in California Specialty Crops

Location: Crop Diseases, Pests and Genetics Research

Project Number: 2034-21220-007-27-A
Project Type: Cooperative Agreement

Start Date: Jul 15, 2019
End Date: Mar 1, 2021

Objective:
This project will address the priorities of developing new tools to detect, eradicate, and control pests and diseases; preventing and managing pests and diseases to minimize economic and environmental harm to specialty crop growers; and enhancing speed and reliability of detection methods. The goal of this project is to develop diagnostics tools to detect and control powdery mildew on specialty crops which will address each of the priorities. Diagnostic tools will allow for the early and rapid detection of powdery mildew in grapes, strawberry, and apple, as well as provide vital information on fungicide sensitivity to major classes of fungicides (QoI and DMI).

Approach:
Assess fungicide sensitivity, stability, and geographic distribution of isolates collected from fresh and wine grapes across two seasons using molecular assays. Sample colonies for quantitative polymerase chain reaction (qPCR) diagnostic assay development. Incubate samples for single chain conidia to develop genetically pure samples. Evaluate fungicide sensitivity to QoI-based chemistry using germination assays and discriminatory doses. Evaluate fungicide sensitivity to DMI-based chemistry using leaf disk bioassays. Evaluate fungicide sensitivity to quinoxyfen using leaf disk bioassays. Validate molecular assays for monitoring resistance to QoI and DMI fungicides in Erisyphe necator and develop markers for other groups (e.g., quinoxyfen). Validate QoI and DMI fungicide-resistance diagnostic markers on previously collected weekly air samples from 100 vineyards. Sequence powdery mildew isolates to identify genetic elements associated with quinoxyfen resistance. Develop diagnostic tools for quinoxyfen. Develop a rapid, in-field diagnostic assay for DMI and QoI fungicide resistance in grape powdery mildew. Evaluate fungicide sensitivity to QoI-based chemistry using germination assays and discriminatory doses. Evaluate fungicide sensitivity to DMI-based chemistry using leaf disk bioassays. Validate the in-field diagnostic assay for DMI and QoI fungicide resistance in grape powdery mildew.