UC IPM Online UC ANR home page UC IPM home page

UC IPM Home

SKIP navigation

 

Research and IPM

Grants Programs: Projects Database

Project description

Pruning for Control of Pierce's Disease. (98FE032)
Program UC IPM competitive research grants program
Principal
investigator
A.H. Purcell, Environmental Science, Policy and Management, UC Berkeley
Host/habitat Grapes
Pest Pierce's Disease Xylella fastidiosa
Disciplines Entomology, Plant Pathology
Review
panel
Applied Field Ecology
Start year (duration)  1998 (Two Years)
Objectives Determine if pruning can eliminate Pierce’s disease from grapevines with symptoms of the disease.
End-year
progress
Severe pruning (just above the graft union) in the winter of 1998-99 successfully regenerated healthy grapevines from trellised vines in Napa Valley that had severe symptoms of Pierce's disease during fall, 1998. Grape varieties used were Cabernet Sauvignon, Merlot, Pinot noir, Chardonnay, and Cabernet franc. Vine ages were from 2 to over 8 years. Recovery rates ranged from 87 to 100%) for vines with the least severe symptoms; from 71 to 95% for vines in the "moderate" severity category; and from 38 to 85% for the most severe category. For the least severe disease category, rates of recovery for pruned vines were not substantially or significantly greater than normal dormant pruning in some plots. Visual ratings of Pierce's disease agreed with results from using a sensitive molecular diagnostic test (Polymerase Chain Reaction) for Pierce's disease for 79% of the least severe category, 80% of the moderate category, and 97% of the severe category. The results demonstrated that it is feasible to regenerate healthy vines from vines with Pierce's disease more quickly by severe pruning than by pulling and replanting the vines. The experimental results suggest that only vines with symptoms near the base of the cane should be severely pruned in order to regenerate a healthy vine. Further research is needed to validate the effectiveness of severe pruning in different viticultural regions and to test the effectiveness of selective pruning of laterals (e.g., cordons) rather than the trunk of the vine.

Top of page


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   web template revised: October 25, 2014 Contact webmaster.