Crop: Table Grapes
Result: Produced clusters that were on average 7.4% heavier with 66.1% less total cull area
Location: Fresno County, California

Summary and Observations

The Flame Seedless grapevines involved in this study each produced an average of approximately 37 primary bunches (clusters). Those vines treated with five foliar applications of Agrostim™ at 1.0 gallon per acre, produced clusters that were on average 7.4% heavier than those receiving only the conventional treatment. Individual bunch weights increased by 6.4% in Agrostim™ treated plots.

One hundred berries selected at random from each of four replicates weighed an average 15% more where the Agrostim™ was applied. Average berry diameters were 6.0% greater where the Agrostim™ was applied compared to the conventional treatment. Brix was essentially unchanged for thetwo treatments.

Medium red color was the most wanted grapes for the fresh market of lunch snacks. Some 63% of the Agrostim™-treated berries were of this color compared to 32% for the conventional alone treatment, a significant increase of 96.9%. More of the remaining berries, percentage-wise, in the Agrostim™ rows were darker in color suggesting the berries matured faster where Agrostim™ was used. Color development was much more uniform where Agrostim™ was applied compared to the conventional applications alone. Correct color was a large consideration for selection of these primary bunches to be included in the fresh market lunch snacks.

The impact of Agrostim™ on cull was significant, as bunches treated with the Agrostim™ had 66.1% less total cull area.

Following picking for the fresh market, harvesters left nearly twice as many primary bunches in the conventional plots compared to those receiving Agrostim™ applications. These remaining bunches were turned into raisins and sold for less profit. The difference in the number harvested for the fresh market represents 6.5 lbs of primary -bunches per vine, on average, going to the fresh market. Only an estimated 85.75% of control bunches were suitable for the fresh market whereas an estimated 95% of bunches treated with Agrostim™ were suitable for this market. This translates to an increases of $2.54 per vine of fresh market grapes which represents a 25.6% increase in profits which is statistically significant.

No phytotoxicity was produced.

Study Details

CROP: Flame Seedless Table Grapes (Planted in 1985)

TEST SITE: Fresno County, California

START DATE: April 14, 1992

PLOT SIZE: Sub-samples from two ten acre fields, subdivided into nine six-row strips



Control: Grower’s standard crop fertilization and protection program

Treatment: Grower’s standard program plus multiple foliar applications of 1.0 gallon per Acre Agrostim™

APPLICATION PROCEDURE: Agrostim added to 500 gallon seed spray set to 50 gallons per acre to 10 Acres


1. April 4 (8-12 in. cane)
2. May 2 (18-24 in. cane)
3. May 20 (50% bloom)
4. June 7 (Berry set – early shattering)
5. June 25 (Sizing)

DATE HARVESTED: July 23-24 (Primary bunches)