(Wines&Vines) - Considering how much cash and work growers spend to keep grapevines healthy, they are surprisingly hard to kill. It’s easy to rip vines out or cut them down, but that doesn’t usually kill them. Living remnants of the roots will remain, hosting pathogens and pests that could threaten future plantings. Responding to the need to replace individual defective vines, replant whole vineyards that have declined, are unpopular varieties or have disease issues, Dr. Brad Hanson, a weed science specialist at the University of California, Davis, discussed how to kill vine roots for pest and pathogen management and re-development at a recent meeting of the Napa Viticultural Technology Group.