1a. Objectives (from AD-416)
Improve the quality and storage life of table grapes by the application of sprays directed into grape clusters in vineyards before harvest.
1b. Approach (from AD-416)
In repeated cluster-directed applications between fruit set and harvest, apply calcium salts, hormonal treatments, reduced-risk fungicides, biological control agents, and other compounds before harvest, then determine their influence postharvest quality (color, texture, maturity, size) and decay (natural incidence of diseases, after artificial inoculation) of table grapes. Documents Trust with CA Table Grape Commission. Log 35964. Formerly 5302-43000-032-11T (11/09).
3. Progress Report
The agreement was established in support of Objective 1 of the in-house project, the goal being to minimize postharvest decay losses of table grapes using biological control, generally-recognized-as-safe or reduced-risk compounds, and thermal treatments. Several vineyards were selected and a variety of growth regulators, elicitors of pathogen defense reactions, and mineral nutrients were applied to developing grape clusters to reduce decay that developed after harvest. Berry color, size, firmness, sugar content, and incidence of decay pathogens were among measurements that were made. With many cultivars, decreases in decay and substantial increases in firmness, sugar content, and/or red color were among the effects observed after applications of potassium salts directly into clusters after flowering.