Progress 05/01/09 to 06/01/12
Outputs
Progress Report Objectives (from AD-416): Our objectives are to: 1) quantify the fungicide-resistance of Botrytis cinerea in San Joaquin Valley table grape vineyards; 2) evaluate the effectiveness of mixtures of fungicides registered in California with potassium sorbate or potassium phosphite to control resistant isolates of B. cinerea and postharvest decay; and 3) evaluate their impact on grape quality. Approach (from AD-416): In repeated experiments with isolates collected from many locations, determine the sensitivity of Botrytis cinerea, the gray mold pathogen, to fungicides now in common use. In vineyard trials, assess the benefits of the addition of two safe, environmentally benign compounds to the fungicides to obtain control of this pathogen and reduce rates of these fungicides. Progress was made on an objective of National Program 306: Quality and Utilization of Agricultural Products Component 1. Quality Characterization, Preservation, and Enhancement. Problem Area 1d. Preservation and/or Enhancement of Quality and Marketability, Objective: Develop environmentally friendly strategies for plant and animal pathogen control. To prolong the storage life of fresh grapes, trials were conducted in a �Thompson Seedless� table grape vineyard, where conventional and certified �organic� fungicides were applied repeatedly before harvest. The incidence of decayed berries was counted one to two months after harvest among grapes from these plots. At the San Joaquin Valley Agricultural Sciences Center in Parlier, repeated applications of the common food preservative potassium sorbate reduced the postharvest incidence of decayed berries by about 70%. This was in comparison to a reduction of about 90% observed after an intensive spray program consisting of several of the best performing �reduced-risk� fungicides. Because it is inexpensive, readily available, exempt from residue requirements, and provides a source of potassium to developing berries to improve their quality, vineyard applications of potassium sorbate are a promising tool. These results were presented to growers in a written progress report to the California Table Grape Commission submitted January 31, 2012.
Impacts
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Publications
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) Our objectives are to: 1) quantify the fungicide-resistance of Botrytis cinerea in San Joaquin Valley table grape vineyards; 2) evaluate the effectiveness of mixtures of fungicides registered in California with potassium sorbate or potassium phosphite to control resistant isolates of B. cinerea and postharvest decay; and 3) evaluate their impact on grape quality. Approach (from AD-416) In repeated experiments with isolates collected from many locations, determine the sensitivity of Botrytis cinerea, the gray mold pathogen, to fungicides now in common use. In vineyard trials, assess the benefits of the addition of two safe, environmentally benign compounds to the fungicides to obtain control of this pathogen and reduce rates of these fungicides. This agreement was established in support of Objective 1 of the in-house project, the goal being to develop integrated and commercially feasible pre-harvest practices and treatments to improve quality and extend the shelf and shipping life of fresh fruit (primarily citrus fruit and table grapes). Trials were conducted in a �Thompson Seedless� table grape vineyard in which conventional and certified �organic� fungicides were applied repeatedly before harvest. The prevalence of decayed berries was counted one to two months after harvest among grapes from these plots. At the San Joaquin Valley Agricultural Sciences Center in Parlier, repeated applications of the common food preservative potassium sorbate reduced the postharvest incidence of decayed berries by about 70%, compared to a reduction of about 90% observed after an intensive spray program several of the best performing �reduced-risk� fungicides. Inexpensive, readily available, exempt from residue requirements, and a source of potassium to developing berries to improve their quality, vineyard applications of potassium sorbate are a promising alternative to conventional fungicides.
Impacts
(N/A)
Publications
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