Brown, Albre Abi (2016-08). Trunk Disease of Grapevines in Texas. Master's Thesis. Thesis uri icon

abstract

  • On a global scale, grapevine trunk diseases (GTDs) remain the greatest limitation to maintaining optimal yield as a vineyard ages. The best method of control is early prevention. However, due to the slow development of symptoms, preventative measures are infrequently employed. Many of the vineyards in Texas are less than ten years old, but with maturation of the winegrape industry will come GTDs. The overall goals of this project were to identify and characterize the fungi responsible for trunk disease in Texas and to raise awareness of these pathogens and promote early prevention as a parameter of disease management. First, three vineyards were surveyed for GTD incidence, severity, and the presence of causative agents. A positive correlation between vine age and disease severity was demonstrated. Second, the project identified the prevalent GTD-causing fungi in Texas wine grape vineyards. Fungi isolated from infected vines showed the presence of all major grapevine trunk diseases previously identified in the US, commonly known as esca proper, Botryosphaeria dieback, Eutypa dieback, and Phomopsis cane and leaf spot. Pathogenicity assays demonstrated disease causality and determined that Lasiodiplodia sp. were the most aggressive of the tested pathogens. Results from the third objective coincide with previous studies which indicate a correlation between spore dispersal and increased precipitation. The information obtained from these studies will be used to formulate GTD management recommendations for Texas wine grape growers.
  • On a global scale, grapevine trunk diseases (GTDs) remain the greatest limitation to maintaining optimal yield as a vineyard ages. The best method of control is early prevention. However, due to the slow development of symptoms, preventative measures are infrequently employed. Many of the vineyards in Texas are less than ten years old, but with maturation of the winegrape industry will come GTDs. The overall goals of this project were to identify and characterize the fungi responsible for trunk disease in Texas and to raise awareness of these pathogens and promote early prevention as a parameter of disease management.

    First, three vineyards were surveyed for GTD incidence, severity, and the presence of causative agents. A positive correlation between vine age and disease severity was demonstrated. Second, the project identified the prevalent GTD-causing fungi in Texas wine grape vineyards. Fungi isolated from infected vines showed the presence of all major grapevine trunk diseases previously identified in the US, commonly known as esca proper, Botryosphaeria dieback, Eutypa dieback, and Phomopsis cane and leaf spot. Pathogenicity assays demonstrated disease causality and determined that Lasiodiplodia sp. were the most aggressive of the tested pathogens.

    Results from the third objective coincide with previous studies which indicate a correlation between spore dispersal and increased precipitation. The information obtained from these studies will be used to formulate GTD management recommendations for Texas wine grape growers.

ETD Chair

publication date

  • August 2016