Issue link: https://read.dmtmag.com/i/654468
18 MARCH 15, 2016 Good Fruit Grower www.goodfruit.com G rapevines require adequate chilling during dor- mancy for uniform bud break the following grow- ing season, but vines in northern growing areas that are exposed to very low temperatures or sud- den extreme low temperatures can be susceptible to damage. Finding and recognizing the signs of this damage is critical for growers in these regions. Buds, canes, cordons, trunks and roots can be damaged when temperatures fall below a vine's particular cold hardiness level, and the vine itself can die. Buds are moderately susceptible to cold damage and cannot be repaired. However, vines also have a compound bud comprised of primary, secondary and tertiary buds that work as a backup plan. The phloem (vascular tissue that conducts sugars and met- abolic products from the leaves to other plant parts) is most susceptible to cold damage in midwinter, but it regenerates itself annually. Xylem, the vascular tissue that conducts water and nutrients from the roots to other plant parts, is the least suscepti- ble to cold damage, but xylem damage is more serious because it Cold DAMAGE Grapes Finding and recognizing the signs of cold damage in grapevines is critical for growers in northern regions. by Shannon Dininny TJ MULLINAX/GOOD FRUIT GROWER Above: Dr. Michelle Moyer, left, shows Stacy and Greg Letendre how to assess damage to grape buds using a two-cut method of exposing the three buds within the vine during winter. Right: If any of the buds are brown — and not green — they were probably damaged by a cold snap.