Ultra Gro Crop Shield and Walnuts


In a recent trial conducted by a third party, Ultra Gro Crop Shield was applied to walnuts to evaluate sunburn control and yield response.


The trial concluded that trees treated with Crop Shield showed:


3.3% Increase in Turnout

10% Increase in Extra Light/Light Nut Meats

25.6% Reduction in Amber Nut Meats

43% Reduction of Dark Amber Nut Meats

The Full Results

Ultra Gro Crop Shield was applied to walnuts to evaluate sunburn control and yield response. There were two treatments, one Ultra Gro Foliar Crop Shield, and an untreated control. Four total applications were made starting at bloom (5/7/21) and concluding one month before harvest (8/17/21). Harvest and the evaluations were mid-September (9/12/21).


Ultra Gro Crop Shield was applied at 1 gal/A to Ivanhoe Walnuts to evaluate for sunburn control and yield response. Four total applications were made starting when ambient temperatures approached 100oF , with subsequent applications occurring approximately every 30 days (5/27, 6/10, 7/12, and 8/17).  Applications were made with a mist sprayer and delivered at 100 gpa. Each plot was 30 wide by 90 feet long consisting of one row of three trees. Each treatment was replicated four times. 


At harvest, both the untreated plots and Crop Shield showed no significant difference in the number of nuts per plot, nut weight per 100 nuts, nut meat weight per 100 nuts, yield pounds per acre, or nut meat yield pounds per acre. The differences begin to show up in greater turnouts. For the assessment there was a 3% increase in turnout. Higher turnouts are indicative of larger nut meats.


The greatest differences were in the color ratings of the nut meats. The color evaluation of the nut meats was categorized in three groups: extra light/light, light amber, and amber. There was a 10% increase in extra light/light nut meats, a 25.6% decrease in amber and a 43% decrease in dark amber (following the USDA guidelines).


Kernel size and pellicle color are key indicators of walnut quality. Good size nuts with light color pellicle bring higher prices for growers.


There were no handling or significant mixing problems during the spray applications of the Ultra Gro Foliar Crop Shield material and no phytotoxicity was observed.

Nut Meat Color


About Crop Shield

Ultra Gro has been treating plants for heat stress for over 30 years using foliar applications of UG Crop Shield, one of our flagship products. Crop Shield contains a mixture of highly effective nutrients and water-soluble biodegradable material. Macro- and micro-nutrients such as nitrogen, phosphorus, potash, zinc, iron, manganese, copper cobalt, and molybdenum are all included. All told, this combination will feed the plant necessary nutrients and protect it from the heat.

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