Pierce's Disease
Research Updates

piercesdisease.cdfa.ca.gov

What is Pierce's Disease?

Pierce's Disease is a bacterial infection, which is spread by bugs that feed on grapevines, particularly the "glassy winged sharpshooter." Grapevines that become infected with PD can quickly become sick and die.

glassy-winged sharpshooter

Grapevine rooting patterns: A comprehensive analysis and a review


  • Author(s): Lakso, A.; Morano, Lisa; Schwass, E.; Smart, D.;
  • Abstract: Grapevines are grown either on their own roots or on rootstocks that represent a mixture of grapevine species and hybrids. Developmental and physiological factors other than phylloxera resistance, lime tolerance, and ease of propagation were not directly considered during rootstock breeding, including rooting patterns. Here, in a comprehensive literature synthesis, we have compiled information concerning rooting depth distributions of grapevine roots from wall profile studies comprising a broad range of soil environments and rootstock genotypes. We considered the distributions based on the asymptotic equation of Y = (1 - beta(d)), where d = soil depth (cm) and Y = the proportion of roots from the surface to depth d. The median value of beta for the root distributions analyzed was 0.9826 and the standard deviation over all observations was 0.0068 (n = 240); most profiles had fitted values of beta generally greater than 0.975. This value places the depth distribution of grapevine roots in the vadose zone among the deepest observed for plants worldwide. The data suggested that soil properties such as the presence of soil profiles impermeable to root penetration, stoniness, and presence of gravel lenses have a greater influence on depth distributions than does genotype, even in deep fertile soils. Genotypic differences were not apparent, although the rootstock O39-16 (beta = 0.9867 +/- 0.0009, mean +/- se, n = 11), with a reputation for deep-rooting behavior, did exhibit deeper root distributions. The analysis also suggests that root characteristics other than root horizontal and vertical spread may need to be considered in order to explain some key rootstock characteristics like scion vigor or drought tolerance.
  • Publication Date: Jan 2006
  • Journal: American Journal Of Enology And Viticulture