Organic viticulture research
in Pennsylvania
Jim Travis, Bryan Hed, and Noemi
Halbrendt
Department of Plant Pathology
Penn State University
Organic production in the US;
1st national certified organic production survey
• Response rate of 87 %
• Organic sales: $3.16 billion total
- CA = $1.15 billion (*number one*)
- WA = $282 million
- PA = $213 million
• Number of organic farms: 14,540 total
- PA sixth (586 or 4 % of the total)
• Organic acres = 4.1 million
• Most significant expense in organic = labor
Lake Erie Regional Grape Research
and Extension Center
Research Program: 3 areas of focus
- Disease control in organic viticulture (*black rot*).
- Transition of Concord grape vineyard to certified organic.
- Soil and vine nutrition in organic grape production
Disease control (black rot) in eastern
organic viticulture is accomplished
through…
• Understanding the pathogens and how they
are affected by…
• Site/Vineyard Selection
• Site Preparation
• Varietal Susceptibility
• Fungicide application
• Sanitation
• Canopy management
Major grape diseases
in eastern viticulture
Downy
mildew
Powdery
mildew
Black rot
Phomopsis cane
and leaf spot
Black rot
symptoms
Leaves
Lesions appear 2
weeks after
infection in spring
Shoots
Dark pycnidia
within lesions
Black rot
• Tan (chocolate milk)
spots on berries
• Berries turn dark brown
with numerous pycnidia
Black rot
• Leaf and shoot tissue susceptible as
long as still expanding.
• Fruit very susceptible from start of
bloom to 3-4 (Concord) to 4-5 weeks
(vinifera) after bloom.
• Fruit highly resistant
by 6 (Concord) to 8
(vinifera) weeks after
bloom.
Black Rot; Biology/Disease
Cycle
• Over-winters in infected fruit (mummies) and
wood (canes) on ground and in trellis.
• Primary cycle - spores released by rain, splashed
to green tissue.
• Spore germination and infection dependent on
wetness duration and temperature
• *New spring cluster stem infections may produce
inoculum in 2-3 weeks – fruit infection often
results from these secondary inoculum sources.
How important are early spring cluster stem infections?
2007 pre-bloom shoot inoculations;
Black rot cluster stem severity → fruit rot severity.
F
r
u
i
t
r
o
t
May 18 inoc.
May 29 inoc.
Pre-bloom cluster stem lesion development
2008 pre-bloom shoot inoculations;
Black rot cluster stem severity → fruit rot severity.
F
r
u
i
t
r
o
t
May 8 inoc.
May 15 inoc.
May 25 inoc.
Pre-bloom cluster stem lesion development
Site Selection:
can determine overall disease pressure
• Maximum air movement and drainage
(low RH)
• Maximum sunlight (no shade)
• Good soil drainage
• Adjacent land use
• Avoid proximity to
water
• Soil quality: fertility,
pH…vigor control
How much does site matter?
Vineyard 1
Vineyard 2
• Concord
• Sunny, well drained,
open
• 3 copper sprays each
year
• 0.1 (2008) to 3 %
(2009) crop loss to
disease.
• Concord
• Wooded on 2 sides,
wet, poor air flow,
some rows shaded
• 6 (2008) and 7 (2009)
copper sprays
• 16 (2008) to 73%
(2009) crop loss to
disease.
*Vineyards are within 5 miles of each other.
Site Preparation
•
•
•
•
Row spacing
Vine spacing
Row orientation
Get weeds, diseases, and insect pests
under tight control BEFORE transition.
Varietal Selection: what’s important
to disease control?
• Sensitivity to copper, sulfur: red hybrids, natives are
sensitive.
• Predisposition to harvest bunch rots: avoid varieties
with tight clusters;
• Disease susceptibility varies tremendously, particularly
to black rot:
- Vidal, Traminette, Elvira, Cayuga least susceptible to
black rot.
- Vitis vinifera most susceptible
- Mid Atlantic is ground zero for grape pathogens (their
turf); organic = use all tools to your advantage.
Varietal susceptibility to black rot;
2009 Leaf inoculations
•
All white
varieties;
sulfur not an
issue.
•
Four French
hybrids vs
Vitis vinifera
(Chardonnay)
•
Chardonnay
many times
more
susceptible.
Varietal susceptibility;
Vidal trials in Erie PA
Powdery mildew on fruit
Powdery mildew on leaves
Downy mildew on fruit
Downy mildew on leaves
Organic chemical control trials 2005-2008
Black rot control: Concord clusters
100
Champion 4 lb + lime
90
Champion 2 lb + lime
80
Lime Sulfur
70
Citrex
60
Yucca
50
Milstop
40
EF 400
30
GC-3
20
Serenade
10
Neptunes Harvest
0
Black Rot Control
Organic chemical control trials 2005-2008
Black rot control under high/low inoculum
pressure: Niagara clusters
100
90
Champion 2 lb +
lime
80
Lime Sulfur
70
Citrex
60
50
Yucca
40
30
Quillaja
20
Serenade
10
0
High inoculum
Low inoculum
Sanitation
• Reduce over-wintering inoculum sources
(infected wood, fruit).
• Sanitize Trellis: Hand prune, removal of
mummies
• Sanitize vineyard floor
- Chop up prunings, infected debris
- Bury (till, disk, hill) mummies, prunings.
• Sanitize vineyard: Remove from vineyard and
bury or burn
Combining Sanitation (removal of mummies from
trellis) and Fungicide for maximum black rot control
80
no fungicide
copper
lime sulfur
70
60
Crop
50
loss
40
2006
(wet)
30
20
80
70
60
Crop
loss 50
40
20
10
0
0
No Mummies
2007
(dry)
30
10
Mummies
no fungicide
copper
lime sulfur
Mummies
No Mummies
Cultural control of
black rot: inoculum
reduction
•
•
Infected fruit (mummies)
are potent sources of
inoculum in the trellis –
‘remove’ to the ground.
(Wilson, Reddick 1909).
• Does timing of removal during dormancy (Oct, Nov,
March) affect spore release next season (May, June,
July)?
• Once on the ground, can soil amendments (compost,
compost tea) further impact spore release?
2
Total ascospore counts (x 10,000) per mummy
when dropped to soil at different times
2006
2007
2
1.5
1.5
1
1
0.5
0.5
October drop
November drop
January
March drop
c c
b
ab
a
ab
a
a
0
0
May
June
July
May
June
July
2
Total ascospore counts (x 10,000) per mummy
when treated with soil amendments.
Mummies were placed in plots in November.
2006
2007
2
No amendment
Compost
Compost tea
1.5
1.5
1
1
0.5
0.5
0
0
May
June
July
No amendment
Compost
Compost tea
May
June
July
1
Total ascospore counts (x 10,000) per mummy
when treated with soil amendments. Mummies
were placed in plots in November.
2007
2008
10
9
0.9
Pomace
Chicken manure
No amendment
0.8
0.7
0.6
8
7
6
0.5
5
0.4
4
0.3
3
bc
0.2
0.1
0
Pomace
Chicken manure
Chicken x Pomace
No amendment
abab
a
b
b
ab
a
May
June
a
Not
significant
2
1
0
July
May
June
July
Canopy management: Pruning
• Mechanical pruning – non selective,
more dead, diseased wood = more
inoculum
• Hand pruning (recommended)
– minimizes old, infected wood
– proper bud number
Spur prune vs cane prune
(wine grapes)
• Spur pruning
- requires cordons
- retains more old wood
- retains more inoculum (pathogen source)
• Cane pruning systems
- Minimizes older wood
- Minimizes inoculum
Canopy management:
Trellis systems
• High wire, no tie
- juice, FH wine
-3D
• Vertical shoot position
- FH, vinifera wine
- 2D (aeration, sunlight, fungicides)
Cluster zone leaf
removal for bunch
rot
•
•
•
•
Reduces shading
Improves aeration, sunlight, and
pesticide penetration
$ - can be mechanized
Timing makes a big difference
- Trace bloom: < compactness,
> spray penetration = less rot
Leaf removal timing
Chardonnay, Before LR
After LR
% rot reduction over 3 yrs
Trace bloom (reduces compactness by 23 %)
2-3 wks post bloom
Veraison (8 wks post)
No Leaf removal
73
49
14
*
2007 Results at FREC; Timing of Canopy
Separation/Leaf Removal on Botrytis.
Chardonnay
%
R
O
T
Riesling
Pinot Noir
a* b b
a*ab b
a* b b
- Early CS/LR most
effective
- Timing of LR more
important than CS?
Summary;
Organic disease
management
•
Start with good site selection
•
Follow with good site prep
• Combine with varietal selection (low sensitivity to
copper/sulfur, black rot, bunch rots)
• Don’t rely so heavily on chemicals: copper/sulfur for
diseases.
• Inoculum management/sanitation – drop infected
material to ground as early as possible, bury inoculum.
• Good trellis/canopy management
• Good weed control