new grape grower workshop nematodes in vineyards files/new grape... · root-knot nematodes female...
TRANSCRIPT
New Grape Grower Workshop
Nematodes in Vineyards John M. Halbrendt <[email protected]>
Nematodes Compared to Pin Head
Nematodes - “The Unseen Enemy”
Nematode Pathogens on Grapevines
Lesion
Root Knot
Ring
Dagger
Others reported but pathogenicity has not
been proven e.g. Lance
Nematode Pathogens in the Mid-Atlantic region
Lesion - serious problem in some areas
Root Knot - problem in sandy soil
Ring - problem in sandy soil
Dagger - most important, virus vector, very
common
Ring nematode, Mesocriconema sp
Feeding damage by Lesion and Ring nematodes
Healthy
Check Damaged roots Feeding creates
wounds
for secondary infections
Poor Vine Establishment
Stunted Growth
Reduced Yield
Shortened Productive Life
Galls on 'Cabernet Sauvignon' caused by
Root-knot nematodes
Female root knot
nematode laying 500 eggs
every 35 days
The Tomato Ring Spot Virus is vectored by the
Dagger nematode (Xiphinema americanum)
The Dagger nematode:
• Very common in the mid-Atlantic region
• Has a broad host range
• Long lived nematode (up to 3 years)
• Weak parasite
• Efficient vector of ToRSV
Tomato Ringspot Virus on ‘Chardonnay’
Hen and chick symptom of ToRSV infection
Broadleaf Weeds – natural reservoir of ToRSV - at least 23 common
weeds are alternate hosts.
Also - ToRSV carried in weed seed and can be graft transmitted 10
Virus Transmission
The virus is transmitted from infected weeds to vines by dagger nematodes 11
DON’T INTRODUCE PROBLEMS
Distribution of ToRSV through propagation
"T" type sampling tools ideal for
collecting most soil samples. When sampling collect cores in a
zig-zag pattern across the site.
*Keep samples cool/from heat and sunlight
Combine 20 subsamples to
make one sample for testing.
A soil sample should not
represent more than 3 - 4 acres
Sampling for Nematodes
Once a nematode problem
develops it is difficult to
correct.
Good nematode management
in vineyards requires
preventive measures.
14
Chemical control:
• Soil Fumigation
• Contact Nematicides
• Herbicides (virus control)
15
16
Biofumigation The control of soil-borne diseases by the release
of isothiocyanates from plant tissues.
Biofumigation Chopped and Tilled Rapeseed (Green Manure)
18
A thick stand of rapeseed can suppress weeds
Rapeseed can provide other benefits
Rapeseed makes a good winter ground cover
19
Photo by Dr. R. Weil
Soil Horizons
A
B
C
The rapeseed taproot can penetrate deep and loosen compacted soil
20
Questions?