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.
3. Progress Report
Postharvest quality is an important aspect of table grapes marketing, but the influence of antifungal materials (such as conventional and certified ‘organic’ fungicides, growth regulators, and mineral nutrients) applied repeatedly directly into table grape clusters during the growing season before harvest on the quality, maturity, and incidence of decay pathogens long after storage is poorly known. In 2009, trials continued to confirm results from 2008, where mineral nutrients and GRAS substances were applied repeatedly before harvest. Preliminary results showed substantial improvements in berry quality could be made by these actions. Preliminary results showed potassium applications caused large and measureable effects on berry quality, while calcium applications did not. Cooperator activity has been monitored by the use of technical meetings, visits to the laboratory, and telephone conversations.