ASHS 2024 Conference

Grapevine virus diseases (GVD) are a leading cause of economic concern in the US grape and wine industry, including in North Carolina (NC). Visual vineyard observations in summer and fall of 2017 revealed GVD-like symptoms across European-style winegrowing regions in NC. These observations prompted a state-wide vineyard survey with two aims, (1) identify and assess the prevalence of common grapevine viruses in NC and (2) develop a GVD testing service for growers in NC. A vineyard survey was conducted after harvest (October

As the growing number of individuals moving to Florida has increased to over 1000 residents on average per day. Also, with the current focus on Florida’s water conservation

With the water regulations getting stricter in California and the climatic conditions getting warmer and drier during grape growing seasons, grape growers are forced to improve irrigation efficiency and eventually conserve water usage. This study was designed to incorporate soil moisture sensors and local above-ground weather stations to estimate grapevine water status with the goal to potentially replace pressure chamber measurement, which is the most popular plant-based method of measuring grapevine water status but labor-intensive and time-consuming. The study was conducted in a Barbera vineyard in Fresno, CA and there were four different regimes used in this study, including 50%, 75%, 100% crop evapotranspiration (ETc) replacement, and an over-irrigated condition (>150% ETc). Three Sony’s soil moisture sensors were installed at 20cm, 37.5 cm, and 75 cm in the soil paired with four time-domain reflectometry (TDR) sensors at 20cm, 37.5cm, 75cm, and 150cm in the soil to continuously monitor additional soil conditions besides soil moisture content. The above-ground weather conditions were collected from a nearby California Irrigation Management Information System (CIMIS) station (

Presently, Vitis vinifera grape production in Alabama and the southeastern U.S. is extremely limited due to Pierce’s disease (PD), caused by the bacterium Xylella fastidiosa (Xf) and vectored by insects from the family Cicadellidae. In 2019, UC Davis grape breeding program has released five PD resistant predominantly V. vinifera cultivars which can help sustain the vinifera grape cultivation in the region. Although these new cultivars are currently available, no V. vinifera grape production and management recommendations exist for Alabama conditions. An experimental vineyard was planted at the Chilton Research Extension Center, AL in 2017 to determine the effect of planting distance on vegetative growth and productivity of PD resistant, predominantly V. vinifera advanced selection ‘502-20’. The experiment utilizes a randomized complete block design consisting of three blocks with three vines per block. Vines were planted at an in-row distances of 1.8m, 2.1m and 2.4m and a between row distance of 3.7m and trained to a Watson system. Vine phenology, vegetative growth, yield, and fruit quality characteristics data were recorded during the period of vine establishment (2019-2023). Our results suggest there was a significant treatment by year interaction effect on pruning weight with the lowest pruning weight of 0.8 kg/vine found for vines at an in-row spacing of 2.1m during 2021. Treatment by year interaction also resulted in the highest yield per vine (28.0 kg/vine) measured for vines planted at 2.4m in 2021. Planting distance of 2.4m resulted in a significant increase of the number of clusters per vine during 2021 and 2022 seasons, while no vine spacing effect was found to account for differences in cluster weight, berry mass, or total soluble solids (TSS). Current results indicate planting distance of 2.4m x 3.7m can increase the yield of ‘502-20’ during the years of vine establishment and contribute to sustainable production of PD resistant predominantly V. vinifera grapes in Alabama conditions. Further research will be conducted to expand current knowledge and assist in the development of management recommendations for the successful production of V. vinifera grapes in the region.

Grapevine propagation depends on the formation of adventitious root formation. Vitis riparia and V. rupestris, two native species of North America, serve as the progenitors for the majority of commercially available rootstocks, especially due to their resistance to Phylloxera and ease of propagation. Despite the presence of at least 20 other native Vitis species in North America, many possessing strong resistances to biotic and abiotic stresses, their utilization has been limited by either poor rooting capabilities or insufficient understanding of their rooting potential. This study aims to achieve two main objectives. Firstly, to assess the rooting capabilities of 208 accessions across 20 different species through a dual approach combining traditional evaluation methods with AI-enhanced image analysis. Secondly, to pinpoint the genomic regions linked to rooting ability via a genome-wide association study, which will aid breeding efforts through marker-assisted selection. Preliminary analyses indicate that rooting capability is not solely species-dependent, as there is considerable variation in performance among accessions within the same species. Ultimately, this research will facilitate the development of new, better-adapted rootstocks, which will be crucial in the face of climate change and the increasing prevalence of biotic stresses.

Commercial blackberry producers use various types of trellising systems to support the canes and prevent damage from wind and added fruit weight. The objective of this study was to determine the fruit yield and quality with a new training and pruning strategy (cordon system) in a T-trellis system. The 2022-23 growing season was the first year of a two-year study to evaluate the conventional winter pruning and training strategy against a modified “cordon” training system, with the Prime-Ark® Traveler cultivar, at the Hampton Roads AREC in Virginia Beach, VA. The study was set up as a completely randomized design with two treatments and six replicates. Each replicate had 3 plants. The conventional pruning and training strategy involved leaving 4 to 6 main canes along with their laterals per plant. The cordon system had 2 to 4 canes pruned to the height of each trellis wire allowing two laterals per cane to extend horizontally along the wire in both directions. The intent was to distribute the fruit weight along the wires, making harvest easier. New primocanes were trained to the wires in the same manner after spent floricanes are removed. All winter pruning was done between 10 and 20 March, 2023. Fertigation was done as per standard extension recommendations. Harvesting was done two to three times per week beginning 30 May and ending 28 August 2023. Fruit yield was collected by replicate and fruits were categorized as marketable Grade 1, Grade 2 or nonmarketable. The nonmarketable fruits were recorded as having white drupelet disorder, diseases, and insect or “other” damage. Fruit size, firmness, total soluble solids (TSS) and pH data were collected on ten Grade 1 berries per harvest week and data were averaged for the season. Statistical analysis was done with two-sample t-test at alpha =0.05. The conventional training and pruning strategy had an overall higher total, marketable and nonmarketable yield. Fruit size was slightly smaller in the cordon system and no differences in firmness, TSS or pH were observed.