Location: Horticultural Crops Production and Genetic Improvement Research Unit
Project Number: 2072-30500-001-021-A
Project Type: Cooperative Agreement
Start Date: Apr 1, 2026
End Date: Mar 31, 2030
Objective:
1. Obj. 1-Refine existing biopolymer formulations using suspension and interfacial interaction strategies: Cooperator will enhance current biopolymer-based preharvest sprays by optimizing suspension stability, dispersion, and surface-active properties to improve adhesion, flexibility, and persistence on grape berry surfaces across growth stages.
2. Obj. 2-Enhance formulation performance by incorporating or mimicking grape cuticle microstructures: Cooperator will develop strategies that incorporate or emulate native cuticle microfeatures, such as epicuticular wax crystallinity, surface roughness, and micro-scale architecture, strengthen integration with cuticle and wax layers during berry development.
3. Obj. 3-Assess how refined spray formulations influence cuticle development and surface microbiota during berry growth: Cooperator will evaluate treatment-driven changes in cuticle formation, permeability-related characteristics, and surface microbiome composition and function over key growth stages.
4. Obj. 4-Conduct small-plot field trials under controlled smoke exposure: Cooperator will test refined formulations in small vineyard plots to quantify persistence, barrier function, and reduced uptake under realistic environmental conditions.
5. Obj. 5-Identify growth-stage-specific application strategies and performance thresholds: Cooperator will define optimal timing and conditions for application and establish performance thresholds consistent with cuticle growth.
Approach:
Obj. 1: Cooperator will refine biopolymer based preharvest spray formulations by improving suspension stability, dispersion, and interfacial behavior on grape berry surfaces. Work will include adjusting solids concentration, ionic strength, and pH to maintain uniform particle distribution and prevent aggregation. Interfacial assessments, such as contact angle, spreading, and surface energy measurements, will evaluate interactions with the grape cuticle. Microscopy will document film continuity and adhesion. These methods will guide improvements in adhesion, flexibility, persistence, and compatibility with cuticle changes during berry growth.
Obj. 2: Cooperator will develop strategies to incorporate or mimic grape cuticle microstructures to strengthen integration of films with epicuticular wax layers. Approaches may include templating to reproduce cuticle like micro-textures and polymer structuring to generate semi crystalline or fibrillar features. Films will be characterized using scanning electron microscopy, optical microscopy, and atomic force microscopy to assess alignment with native surface patterns and mechanical properties. These activities will identify design principles that improve film-cuticle integration across growth stages.
Obj. 3: Cooperator will evaluate how refined formulations affect cuticle development, permeability related properties, and surface microbiome dynamics. Treated and untreated berries will be sampled across key phenological stages. Analyses will include cuticle thickness, surface wettability, and indicators of barrier function. Microbiome characterization will be conducted to evaluate the effects of refined formulations on the microbial diversity, functional property, and core microbe identification. Integrated data will reveal how formulations shape physiological and microbial processes during berry development and inform optimal application timing.
Obj. 4: Cooperator will conduct small plot field trials to evaluate formulation performance under controlled smoke exposure. Formulations will be applied using standard agricultural methods to ensure realistic deposition and surface coverage. After smoke exposure, berries will be analyzed for surface and internal concentrations of volatile phenols and phenol glycosides, and for potential impacts on cuticle and wax barrier function and microbiome composition. This approach will provide practical, on vine evidence of protective effectiveness and potential consequences for fungal and bacterial communities colonizing the fruit surface.
Obj. 5: Cooperator will synthesize results from formulation refinement, microstructural enhancement, biological assessments, and field trials to determine growth stage specific application strategies. Analyses will link cuticle growth, microbial shifts, and formulation performance metrics, including adhesion, spreading, and persistence, to define operational guidance for vineyard deployment.