Virginia Tech
Advancing Sustainable Grape Downy Mildew Management: Biopesticide Trials and Risk Assessment System
Abstract
dc:description.abstractGrape downy mildew, caused by Plasmopara viticola, significantly damages grape crops (Vitis spp.), reducing yields by up to 75% in unprotected vineyards. The Eastern US faces limited fungicide options due to resistance development and potential legal restrictions on EBDC and captan. The first study evaluated various biopesticides and conventional fungicides in field and greenhouse trials from 2024 to 2025 across multiple Vitis vinifera cultivars in Virginia. Among biopesticides, the GEA 249 complex, Bacillus mycoides Isolate J, and Pseudomonas chlororaphis strain AFS009 showed results comparable to conventional fungicides such as copper octanoate, achieving up to 74% disease control. The second study focused on developing a downy mildew forecasting system using a model-based weather data approach that does not rely on physical weather stations. We also collected infection data from the field between 2022 and 2025 to evaluate two types of models we developed. The mechanistic model, which combined two published empirical models, outperformed the empirical models based on field trial data, achieving 60.3% accuracy in predicting downy mildew incidence, demonstrating its potential to reduce fungicide overapplication as part of integrated pest management.
Degree
thesis:*- Name thesis:degree_name
- Master of Science in Life Sciences
- Level thesis:degree_level
- masters
- Discipline thesis:degree_discipline
- Plant Pathology, Physiology and Weed Science
- Department dc:contributor.department
- Plant Pathology, Physiology and Weed Science
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2025
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Ames, Jonathan Eugene
- Chair dc:contributor.committeechair
-
- Nita, Mizuho
- Committee members dc:contributor.committeemember
-
- Baudoin, Antonius B.
- McCall, David Scott
Subjects
dc:subject × 4Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
- Language dc:language.iso
- en
Identifiers
dc:identifier.*- Dc Identifier Other
- vt_gsexam:45058
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/139858