What is Killing my Vines? Plant Failure in New Vineyards

What is Killing my Vines?
Plant Failure in New Vineyards
Bill Cline, Plant Pathology Department
North Carolina State University
Horticultural Crops Research Station
Castle Hayne, NC
There are lots of possible causes
for a dead grape vine . . .
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Poor plants
Poor site
Poor care
Drought
Drowning
Animal damage
Storm damage
Wrong cultivar
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Herbicide injury
Fertilizer injury
Cold injury
Insects
Diseases
Weed competition
Lightning
Weedeater blight
But site selection is the most
important decision you will make
Site Selection
Muscadines do not like “wet feet”!
Use a county soil map to determine
whether your site is suitable:
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Soil classification
Soil profile
What crops grow well
on your soil type?
External drainage
Internal drainage
Most zones are
irregular in shape
Following recent heavy rains in SENC (5+ inches)
many growers reported young vines dying
In most cases, vine death was associated with wet
spots in fields, or areas of “tight” soils with poor
internal drainage
New buds emerging from “dead” or
“drowned” vine after flooding event
Weak shoots emerging from trunk
of vine defoliated by flooding
Herbicide injury
Gramoxone used for sucker control
can girdle young vines
Gramoxone-injured trunk of 2-yr-old ‘Carlos’
vine (with bark removed to show damage)
In this instance, gramoxone applied to
suckers was translocated up the vine,
burning the leaf veins throughout the vine
Girdled vines (right) can be cut off and
a new shoot re-trained from the stump
Plant source
Weak plants may be infected by a fungal disease
and should be culled prior to planting
Cultivar Selection
Supreme is a very productive, large fruited cultivar, but has
a reputation for poor vine survival. Two of three vines at
Castle Hayne have been cut back to the ground.
‘Fry’ vines at Castle Hayne have been productive for 5 yr,
now suddenly are dying out. Possible root borer injury?
Site was previously in grapes for 20+ yrs. Alternating rows
of ‘Triumph’ are not affected
Lightning
Lightning shattered this post and killed several
vines in a circular area
Suspected lightning strike on bearing vines
damaged most plants in this single row
Re-growth from base of vines in
suspected lightning-struck row
Close-up of injured trunk above regrowth
Vines in varying stages of recovery
in the affected row
Re-growth beginning at base of
injured vine
Cold Injury
Shoot damage in November on an
excessively vigorous vine
Shoot damage in November
(cont’d)
Shoot damage in November
(cont’d)
Secondary invaders
Fungal pathogens
„ Ambrosia beetles and other insects
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Aerial roots may indicate a stressed vine,
due to cold or other trunk injury, or perhaps
grape root borer damage
Cultures of a stem-infecting fungus
(Botryosphaeria sp.) recovered from
cold-damaged grape vines
Old trunk showing remnants of
ambrosia beetle damage
Unidentified trunk borer found in “Triumph”
muscadine vines at Castle Hayne.
Fungal mycelia (white “threads”) and vascular
discoloration on an infected grape root. This type
of infection is fairly rare on muscadines.
Hurricanes may damage vines and trellis;
once down, the heavy, fruit-laden vines are
difficult to lift and prone to breakage
QUESTIONS?