Giesco
INVESTIGATING THE SPREAD AND EFFECT OF GRAPEVINE RED BLOTCH VIRUS IN CALIFORNIA-GROWN ZINFANDEL INVESTIGACIÓN DE LA PROPAGACIÓN Y EFECTO DE LA ‘GRAPEVINE RED BLOTCH VIRUS’ EN CALIFORNIA-CULTIVADO ZINFANDEL
WUNDERLICH, Lynn R.1; BOLLINGER, Michael L.2; SHAFFER, Meredith3; PRETO, Cindy R.2; BAHDER, Brian4; ZALOM, Frank G.2; SUDARSHANA, Mysore3 1 University of California Cooperative Extension-Central Sier ra, 311 Fair Lane, Placerville, CA. 95667, U.S.A. 2Department of Entomology and Nematology, University of California-Davis, Davis, CA. 95616, U.S.A. 3United States Department of Agriculture-Agricultural Research Service, Department of Plant Pathology, University of California, Davis, CA. 95616, U.S.A. 4Department of Entomology and Nematology, Ft. Lauderdale Research and Education Center, University of FloridaFt. Lauderdale, Ft. Lauderdale, FL. 33314, U.S.A. *Corresponding author: lrwunderlich@ucanr.edu
Abstract: Grapevine red blotch virus (GRBV) is a major concern for California winegrape growers since its discovery in 2012. Negative impacts on juice have been reported, though inconsistent. A treehopper, Spissistilus festinus, transmitted GRBaV in strict laboratory studies, but field evidence of transmission is lacking. Many GRBaV-infected vines originate from the nursery and are being removed. Our goal is to study GRBaV spread and its effects on juice quality in a dry-farmed own-rooted Zinfandel (Vitis vinifera) vineyard in Amador County. The vineyard was field grafted from a block that, in turn, was grafted from a 1923 planting. Between 2015 and 2016, 1224 vines from three blocks were visually mapped for symptoms, and petioles were collected from a subset of vines for confirmation of GRBV infection by qPCR. Overall infection in 2015 was rated 24.7%; and increases observed visually in 2016 were 18.2%, 19.9%, and 7.1% for blocks 1, 2 and 3, respectively. Girdled vines were observed in fall and S. festinus were collected. Prior to harvest, thirty berries from ten healthy and ten GRBV-infected vines were collected. Berry weight, pH and total soluble solids (TSS) of juice were measured. Infected berries were heavier and mean pH slightly lower in 2015. Mean TSS was 7.75 and 4.34 °Brix lower in berry juice from infected vines compared to healthy in 2015 and 2016, respectively.
Keywords: Grapevine red blotch virus, Zinfandel
Abstract: Grapevine red blotch virus (GRBV) is a major concern for California winegrape growers since its discovery in 2012. Negative impacts on juice have been reported, though inconsistent. A treehopper, Spissistilus festinus, transmitted GRBaV in strict laboratory studies, but field evidence of transmission is lacking. Many GRBaV-infected vines originate from the nursery and are being removed. Our goal is to study GRBaV spread and its effects on juice quality in a dry-farmed own-rooted Zinfandel (Vitis vinifera) vineyard in Amador County. The vineyard was field grafted from a block that, in turn, was grafted from a 1923 planting. Between 2015 and 2016, 1224 vines from three blocks were visually mapped for symptoms, and petioles were collected from a subset of vines for confirmation of GRBV infection by qPCR. Overall infection in 2015 was rated 24.7%; and increases observed visually in 2016 were 18.2%, 19.9%, and 7.1% for blocks 1, 2 and 3, respectively. Girdled vines were observed in fall and S. festinus were collected. Prior to harvest, thirty berries from ten healthy and ten GRBV-infected vines were collected. Berry weight, pH and total soluble solids (TSS) of juice were measured. Infected berries were heavier and mean pH slightly lower in 2015. Mean TSS was 7.75 and 4.34 °Brix lower in berry juice from infected vines compared to healthy in 2015 and 2016, respectively.
Keywords: Grapevine red blotch virus, Zinfandel