Supplemental Foliar Nutrients Effects on Fruit Quality and Yield of Two New Primocane Blackberry Cultivars

Supplemental foliar nutrient products are applied by some berry growers to improve sugar content, fruit quality and yield; however, there is insufficient evidence that these applications increase fruit quality or yield when applied at the recommended label rates. Virginia growers have limited information on two new thornless, primocane cultivars, ‘PrimeArk® Freedom’ and ‘PrimeArk® Traveler’. These cultivars, studied over two fruiting seasons, beginning in 2016, are considered compatible for hardiness zones 6-9. The study was conducted at the Hampton Roads Agricultural Research and Extension Center (USDA, Zone 8a) with thirty-six (36) PrimeArk® Freedom and PrimeArk® Traveler plants, respectively, established using white woven polyethylene ground cover on raised beds and supported by T-post trellises. The objective of the study was to determine if application of supplemental foliar treatments reflected increases in sugar content, yield and overall fruit quality. Three foliar nutrient treatments were applied using recommended label rates of: AgGrand (4-3-3); K-Ace (0-0-25); Sugar Express® (40-10-40). An untreated control that received no supplementary nutrient was included in the study. Six foliar application treatments were applied (April 17, May 5, May 27, June 11, June 25 and July 16 in 2017) at various growth stages from pre-bud to bloom through harvest. There were no significant differences between control and those that received foliar treatments, on plant growth, yield, sugar content or overall fruit quality. This study presents the results of foliar nutrient product effects on thornless, primocane varieties and will be repeated in the 2018 growing season.