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Diseases of Olive Elizabeth J. Fichtner UCCE, Tulare County
Diseases of Olive Elizabeth J. Fichtner UCCE, Tulare County
Olive Knot Disease Pseudomonas savastanoi formerly P. syringae Most important disease on olive worldwide.
Geographic distribution expanding: Egypt Nepal Australia Turkey Girdles stems, branches, trunks
Affects fruit flavor
Passive entry
Leaf scar susceptibility—spring rains.
Factors promoting disease
Frost or hail damage
Harvesting during/before rain
Pruning during/before rain
Mechanized harvest?
Mechanical Harvest Tulare County 2010
Less than 2% of scaffolds damaged in mechanically-harvested rows.
Statistically less damage to scaffolds and large branches in mechanically-pruned plots.
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Machine Harvest
Hand Harvest
Cultivar Susceptibility to Olive Knot
No “immunity” observed across cultivars tested.
Difference in varietal susceptibility seen at low inoculum levels.
Picual and Gordal Sevillana: propensity for secondary knot formation.
29 Cultivars of olive tested 21 Strains of P. savastanoi
Penyalver, et al. Phytopathology, 2006
Recent research from Spain and Italy Epiphytic population serves as primary inoculum.
Pathogen may be introduced on asymptomatic nursery stock.
Pathogen may be translocated locally in xylem vessels.
MANAGEMENT • Avoid pruning/harvesting during rainy season. • Post-harvest Cu-based bactericide in late fall; second application in spring if needed.
Need for alternatives to Cu-based bactericides:
New orchard design/dense plantings enhance risk of disease. *Hedgerow table olives *Trellised oil olives Mechanized harvest
Decreased sensitivity to Copper
Film-Coating Polymers
Non-phytotoxic Weathering/persistence properties
Gas-permeable Some OMRI Listed
Biodegradable
Trade Name Chemistry Company Purpose Validation NOTE
Vapor Gard Di-1-p-menthene
Miller Chemical and Fertilizer Co.
Antitranspirant Powdery mildew/barley, squash Southern rust/maize
Nu-Film P Poly-1-p-menthene
Miller Chemical and Fertilizer Co.
Extender- sticker
Powdery mildew/ barley OMRI Listed
Wilt Pruf Di-1-p-menthene Wilt-Pruf Products Inc
Antitranspirant Leaf blight/sorghum
Bond Synthetic latex and 1,2-Propanediol and alcohol ethoxylate
Loveland Products, Inc.
Spreader-sticker
Powdery mildew/barley
Anti-Stress 550
Cross-linked carbon acrylic latex polymer Polymer Ag. Antitranspirant
Protection of tissue cultured walnut roots
Bio-film
Alkylaryl-polyethoxyethanol, free and combined fatty acids, glycol ethers, di-alkyl benzenedicarboxylate, and isopropanol
Callo Ag Chemical Inc
Spreader- sticker
Leaf rust/wheat Can’t locate
Folicote Wax emulsion Wendell Trading Co
Spreader- sticker
Leaf rust/wheat Singapore!
Three Studies in 2011 1) Potted Plant—natural inoculum; whole plant. 2) Potted Plant—natural inoculum; leaf scars. 3) Mature tree—inoculated; leaf scars.
Influence of polymers on Cu persistence assessed after 3 applications
0
50
100
150
200
250
300
No Cu Cu
23 days post first application
Cu
(p
pm
)
A
B
0
50
100
150
200
250
300
350
400
Water VaporGard NuFilm Anti-Stress 550
Cu
(p
pm
)
Film Forming Polymer Treatment
64 days post first application 44 days post second application
No Cu Cu A
B B
B
C C C C
0
50
100
150
200
250
300
350
No Cu Cu
151 days post first application 43 days post third application
A
B
Cu
(p
pm
)
Why did the synthetic polymer enhance Cu persistence after 2nd application?
0 0.2 0.4 0.6 0.8
1 1.2 1.4 1.6
Pre
cip
itat
ion
(in
che
s)
1st application 2nd application 3rd application
0 10 20 30 40 50 60 70 80 90
Tem
pe
ratu
re (
F)
Temperature Max Temperature Min
0
100
200
300
400
500
600
700
Sola
r R
adia
tio
n (
Ly/d
ay)
Solar Radiation
0
20
40
60
80
100
120
140
160
Water VaporGard NuFilm P Anti-Stress 550
No Cu
Cu
A A
B B B B B B
2012: 55 Days Post-Kocide 3000 application C
u (
pp
m)
P≤ 0.0001
0
100
200
300
400
500
600
700
Sola
r R
adia
tio
n (
Ly/d
ay)
Daily Solar Radiation
0 0.2 0.4 0.6 0.8
1 1.2 1.4 1.6
Pre
cip
itat
ion
(in
che
s)
Daily Precipitation
0 10 20 30 40 50 60 70 80
Tem
pe
ratu
re (
°F)
Daily Max and Min Temperature
1st application 2nd application
0 0.2 0.4 0.6 0.8
1 1.2 1.4 1.6
Pre
cip
itat
ion
(in
che
s)
1st application 2nd application 3rd application
0.4% 0.13% 5.94%
2011: Timing of infection of labeled leaf scars
Majority of infections occurred in Spring
Disease Incidence, November 2012: Potted Plants
No BLOCK affect (P≤0.32)
No POLYMER affect (P≤0.12) No CULTIVAR affect (P≤0.44) Cu affect (P≤0.01)
0
2
4
6
8
No Cu Cu
Disease Incidence
# ga
lls/p
lan
t
Disease severity data: December 2012 No BLOCK affect (P ≤ 0.16) No Cu affect (P ≤ .47) No Polymer affect (P ≤ .93)
Arcsine transformation of percent data; ANOVA Polymer*copper* inoculum level: p≤0.045
0
10
20
30
40
50
60
70
80
90
100
No Polymer Nu Film P Vapor Gard Anti-Stress 550
No Kocide Kocide
0
10
20
30
40
50
60
70
80
90
100
No Polymer Nu Film P Vapor Gard Anti-Stress 550
No Kocide Kocide
Dis
ease
inci
den
ce (
% in
fect
ed n
od
es)
104 CFU/ml 108 CFU/ml
A
A
AB AB
BC BCD CDE CDE CDEF
DEFG EFG EFG EFG
FG G G
Whole Tree: Leaf scars treated with polymer/Cu combinations and inoculated with Psv
No affect of Cu at low inoculum level, regardless of polymer presence. Polymer presence did not improve Cu efficacy at high inoculum level. Polymers did not reduce infection by Psv.
Endophyte Assessemnt Is Psv systemic?
Paired Symptomatic and Asymptomatic branches Sampled in May 2011 and November 2011 Plated on KB and PVF-1 media
1 colony of Psv from symptomatic Manzanillo branch No isolation of Psv from asymptomatic branches on otherwise symptomatic trees. 1 isolate of non-fluorescent Psv was found in May 2011 To be repeated in 2012
TOP BOTTOM BOTTOM TOP
Epiphyte assessment
Two techniques:
Leaf Press
Leaf Wash
Two neighboring sites (Arbuckle, CA)
Heavily symptomatic and asymptomatic
Is pathogen present in absence of disease (Nickels Soils Lab)?
**More total bacteria/leaf at Nickels than at neighboring site **More total bacteria on top of leaf than bottom
0
100000
200000
300000
400000
500000
600000
700000
800000
Lindsay Exeter Ivanhoe Arbuckle Arbuckle Willows Artois Orland Corning Corning Butte Corning
Corning
PVF
KB
KB Fluor
Bac
teri
al c
ou
nts
cfu
/ml
Epiphyte assessment
Southern SJV Sacramento Valley
0
100000
200000
300000
400000
500000
600000
700000
800000
Lindsay Exeter Ivanhoe Arbuckle Arbuckle Willows Artois Orland Corning Corning Butte Corning
Corning
PVF
KB
KB Fluor
Bac
teri
al c
ou
nts
cfu
/ml
Disease Severity does not relate to bacterial populations on leaves * PVF selective medium is NOT selective in our system. * Non-fluorescent strains of Psv * Differential sensitivity to Cu (A. Rhouma)
Olive Epiphyte Assessment: January 2012
Verticillium wilt Soilborne fungus: Verticillium dahliae Wide host range: over 300 plants Common crops affected in California include: cotton, solanaceae, cucurbitae, strawberry.
Symptoms of Verticillium on olive • flagging (symptoms on individual branches) • wilting, chlorosis, defoliation. • xylem discoloration not effective diagnostic tool in olive; confirmation requires culture and/or PCR
Verticillium Disease Cycle
Microsclerotia in soil; Germinate in response to root
Fungus colonizes vasculature, inhibits water transport
Fungus sporulates inside the plant
Symptom development
Microsclerotia form in plant tissue
Decomposing tissues release microsclerotia to soil.
Management of Verticillium wilt in olive
• Pathogen exclusion—plant in uninfested soil. * Avoid planting in former cotton/solanaceae/cucurbit ground. * Soil test for determination of microsclerotia population. (< 1 microsclerotia/g soil) • Pre-plant non-host cover crops (ryegrass, sudangrass, crucifer) for multiple years. • Pre-plant fumigation
with methyl bromide and chloropicrin. • Summer flooding.
Post-plant solarization has had mixed results • Dependant on successful elevation of soil temperatures. Study in Turkey: 45 day solarization from July 15-Sept 1 *reduced population to undetectable levels * reduced disease incidence and severity
* Promoted plant recovery and symptom remission.
Study in Spain: *No affect on disease incidence or severity •Promoted tree recovery in soils with low inoculum levels.
Yildiz and Benlioglu, 2010
Image from a kibbutz in Israel Lopez-Escudero and Blanco- Lopez, 2001
Choose Verticillium Resistant/Tolerant Cultivars
• More options for olive oil growers than table olive growers.
Cultivars exhibiting some tolerance/resistance Ascolano Aglandau Frantoio Coratina Frangivento Oblonga Koroneiki Kalamon Empeltre
Cultivars susceptible to infection Arbequina Arbosana Bouteillan Hojiblanca Manzanilla Mission Picual Picudo Leccino Gordal Sevillano Picholine
Resistant rootstocks will not protect the
scion!
Peacock Spot/Olive Leaf Spot/Bird’s Eye Spot Fungal pathogen: Spilocaea oleaginea
Symptoms-typically in lower canopy And north side of tree Sooty blotches Circular spots (0.1-0.5 inch diameter) Yellow halo around spots Premature leaf drop may affect bloom and subsequent yield.
• Outbreaks are sporadic; several years of disease may be needed to cause economic damage
MANAGEMENT Cu-based fungicide in late fall. Second application (prior to mid-January)- questionable value
Pathogen oversummers in infected leaves
remaining on the tree
Dry/hot summer conditions inhibit disease progress (ie. sporulation/germination)
Fall/winter/spring rains induce sporulation
Spores (conidia) disseminated by rain
Acknowledgements: Dr. Bruce Kirkpatrick, UC Davis George Kasun, UC Davis Carolyn DeBuse, UCCE Yolo and Solano Cos. Bill Krueger, UCCE Glenn and Tehama Cos. Dr. Louise Ferguson, UC Davis Dr. Ali Rhouma, Olive Tree Institute, Tunisia
