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Department of Employment, Economic Development and Innovation
Elio JovicichChrys Akem Gerry MacManus
Downy mildew Powdery mildew
INTEGRATED MANAGEMENT OF POWDERY AND DOWNY MILDEWS IN ZUCCHINI
INTEGRATED MANAGEMENT OF POWDERY AND DOWNY MILDEWS IN ZUCCHINI
Agri-Science Queensland, DEEDI, Ayr, Queensland, Australia
2© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Downy mildewPseudoperonospora cubensis
Powdery mildewPodosphaera xanthii
Issues with disease spread and control• Sequential plantings• Proximity between crops; different growth stages• Infected crops sometimes abandoned• Carryover inoculum becomes exposed to multiple
sprays of the same active ingredient• Overuse of systemic fungicides favour the survival
and proliferation of resistant pathogen strains• Disease control sometimes ineffective
Foliar diseases in zucchini in North Queensland, Australia
• Queensland grows 73% of a total area (2,219 ha) with zucchini & squash in Australia
• In North Qld., field crops grow from March-November• Warm and dry; light morning dews; few rain events
Dry Tropics
3© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Poster # 1
• To screen cultivars for low reaction to foliar diseases
• To measure efficacy of spray products alternative to conventional systemic and contact fungicides
Oral Session 9Thursday 10:45
Improving disease control through integrated managementImproving disease control through integrated management
• To identify programs that reduce the use of conventional systemic and contact fungicides by including alternative spray products and cultivars with disease resistance
Oral Session 5Tuesday 16:15
• To monitor and detect loss of sensitivity or resistance of powdery mildew strains to systemic fungicides
Poster # 41
Objectives of this and related research presented in this symposium
4© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Reactions of zucchini cultivars to powdery mildew and downy mildew in field trials conducted at Bowen and Ayr in 2008
PaydirtCrowbarCLX29881
582-6 Caroline
CalidaAmanda
Zest
HMX5702
7708Congo
Houdini
Golden Rod
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
Rel
ativ
e se
verit
y of
PO
WD
ERY
MIL
DEW
(Bow
en –
Pla
ntin
g 19
Jun
e)
Relative severity of DOWNY MILDEW(Ayr – Planting 29 April)
Nodisease
Nitro
5© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Relative effectiveness of alternative spray products for management of foliar diseases in zucchini. North Queensland field trials.
Spray product Downy PowderyBion ●●● * ●● *Microthiol ●●● ●●●Tricop ●● ●●●Trilogy ● ●●AgriFos 600 ●●● ●●milk ● ●●Synertrol Horti Oil ● ●●Timorex ● ●●Enhance KCS ● ●●Stand SKH ● ●●Peratec ● ●CalAgri 50NF ● * ●● *Ecocarb ● ●●
Relative disease suppression to conventional fungicides and unsprayed controls.Weekly sprays at runoff volumes
●●● Good to medium ●● Medium to low ● Low to none * Some phytotoxicity
or yield reduction observed
6© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Main constituent ingredients and commercial products used in spray programs
Commercial product Acronym Active ingredient Formulation Distribution in AU Alternative
Agri-Fos 600® AF Phosphorus acid 600 g/L Agrichem Bion® (= Actigard 50WG®) BN Acibenzolar-s-methyl 500 g/L (= 500 g/kg) Syngenta Crop Protection Tricop® TP Copper octanoate 18 g/L Colin Campbell Chemicals
Conventional
Acrobat SC® + Mancozeb AMZ Dimethomorph + Mancozeb 500 g/L + 750 g/kg BASF Australia Farmoz Amistar 250 SC® AR Azoxystrobin 250 g/L Syngenta Crop Protection Mancozeb 750® MZ Mancozeb 750 g/kg Farmoz Nimrod® ND Bupirimate 250 g/L Farmoz Bravo® BV Chlorotalonil 720 g/L Syngenta Crop Protection
Different sulphur formulation
Microthiol Disperss® MD Micronized sulphur 800 g/kg Nufarm
7© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
• Selected zucchini cultivars with different reactions to foliar diseases Relative resistance to the diseaseCultivar Seed company Powdery mildew Downy mildewHoudini Syngenta Low Low Calida Clause Medium Medium to Low Nitro SPS High Medium Paydirt Syngenta High Medium
• Selected foliar disease spray programs used on zucchini cultivars
TreatmentsTreatments
Weeks from planting 1 2 3 4 5 6 7 8 Spray dates First crop planted 2 June 2010 10 June 17 June 24 June 1 July 7 July 14 July 21 July 28 July Second crop planted 3 Aug 2010 13 Aug 19 Aug 26 Aug 2 Sep 9 Sep 16 Sep 23 Sep --
Spray program a) BN-BN-BN-TP-MD-TP-MD-TP Bion Bion Bion Tricop M.Sulf. Tricop M.Sulf Tricop b) AF-AF-AF-TP-MD-TP-MD-TP AgriFos AgriFos AgriFos Tricop M.Sulf Tricop M.Sulf Tricop c) AF-AF-AMZ-TP-MD-TP-MD-TP AgriFos AgriFos Acro+MZ Tricop M.Sulf Tricop M.Sulf Tricop d) AMZ-AR-MZ-ND-BV-MD-BV-MD Acro+MZ Amistar Mancozeb Nimrod Bravo M.Sulf Bravo M.Sulf e) No spray -- -- -- -- -- -- -- --
• Four cultivars under 4 spray programs and an unsprayed control
8© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
9© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
0
5
10
15
20
25
30
35
1-Jun 11-Jun 21-Jun 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug 30-Aug 9-Sep 19-Sep 29-Sep
Minimum temperatureMaximum temperature
0
10
20
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70
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90
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1-Jun 11-Jun 21-Jun 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug 30-Aug 9-Sep 19-Sep 29-Sep
Air
rela
tive
hum
idity
(%)
0
20
40
60
80
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120
RainfallRelative humidity 9 am
1st Cropplanted 2 June
2nd Cropplanted
3 August
Air
rela
tive
hum
idity
(%)
Air
tem
pera
ture
(ºC
)
Rai
nfal
l (m
m)
Maximum and minimum day air temperatures and air relative humidity and rainfall, in Ayr in 2010
6 mm 165 mm
Downy mildew 195 %-days 1115 %-days
Powdery mildew 115 %-days 65 %-days
Severity in unsprayed plants
10© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Cumulative severity (AUDPC) of powdery mildew and downy mildew in 4 zucchini cultivars under 5 spray programs for foliar disease management
First planting, 2 June 2010
Calida
-100
0
100
200
300
400
500
-100 0 100 200 300 400 500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Nitro
-100
0
100
200
300
400
500
-100 0 100 200 300 400 500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Paydirt
-100
0
100
200
300
400
500
-100 0 100 200 300 400 500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Houdini
-100
0
100
200
300
400
500
-100 0 100 200 300 400 500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Pow
dery
mild
ew(%
-day
s)
Downy mildew (%-days) Downy mildew (%-days)
Downy mildew (%-days) Downy mildew (%-days)
Pow
dery
mild
ew(%
-day
s)
Pow
dery
mild
ew(%
-day
s)Po
wde
ry m
ildew
(%-d
ays)
Spray programs only reduced powdery mildew in Houdini
95%91%
No effects from spray programs
No effects from spray programs
a) BN-BN-BN-TP-MD-TP-MD-TP b) AF-AF-AF-TP-MD-TP-MD-TP c) AF-AF-AMZ-TP-MD-TP-MD-TP d) AMZ-AR-MZ-ND-BV-MD-BV-MD e) No Spray
11© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Cumulative severity (AUDPC) of powdery mildew and downy mildew in 4 zucchini cultivars under 5 spray programs for foliar disease management
Second planting, 3 August 2010
Calida
-100
0
100
200
300
400
500
0 500 1000 1500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Nitro
-100
0
100
200
300
400
500
0 500 1000 1500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Houdini
0
100
200
300
400
500
0 500 1000 1500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Paydirt
-100
0
100
200
300
400
500
0 500 1000 1500
Downy mildew (%-days)
Pow
dery
mild
ew
(%-d
ays)
Pow
dery
mild
ew(%
-day
s)
Downy mildew (%-days) Downy mildew (%-days)
Downy mildew (%-days) Downy mildew (%-days)
Pow
dery
mild
ew(%
-day
s)
Pow
dery
mild
ew(%
-day
s)Po
wde
ry m
ildew
(%-d
ays)
28%
37%
No effects from spray programs
No effects from spray programs
Program with Bion decreased downy mildewseverity
Program with Bion decreased downy mildewseverity
a) BN-BN-BN-TP-MD-TP-MD-TP b) AF-AF-AF-TP-MD-TP-MD-TP c) AF-AF-AMZ-TP-MD-TP-MD-TP d) AMZ-AR-MZ-ND-BV-MD-BV-MD e) No Spray
12© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
0 5 10 15 20 25 30
Calida
Houdini
Nitro
Paydirt
Total yield (t/ha)
a
a
b
c
Fruit yield main effects for cultivars
Second planting, 3 August 2010
First planting, 2 June 2010
0 5 10 15 20 25 30
Calida
Houdini
Nitro
Paydirt
Total yield (t/ha)
d
c
a
b
Under low downy mildew pressure, yields were greater in sensitive cultivars
Under high downy mildew pressure, yields were greater in cultivars withmoderate resistance
13© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
444
223
309
348
0
0 100 200 300 400 500
Cost of spray program ($/ha) [Includes spray product only]
0 5 10 15 20 25
Total yield (t/ha)
a
b
e
ab
a
a) BN-BN-BN-TP-MD-TP-MD-TP
b) AF-AF-AF-TP-MD-TP-MD-TP
c) AF-AF-AMZ-TP-MD-TP-MD-TP
d) AMZ-AR-MZ-ND-BV-MD-BV-MD
e) No Spray
Marketable fruit yield and estimated costs of spray programs
Second planting, 3 August 2010
14© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Conclusions
• Under high disease pressure, the use of both, cultivars with moderate resistance and programs with alternative fungicides, were as effective as a selected program with conventional fungicides
• Some of the tested alternative products are available and can be cost effective if used in programs with other spray products
• An area-wide plan for managing these diseases should integrate the use of crop genetic resistance to the diseases, products alternative to conventional fungicides, effective conventional fungicides, and crop hygiene practices
• Integrated programs should also prolong the life of effective systemic fungicides
15© The State of Queensland, Department of Employment, Economic Development and Innovation, 2010
Acknowledgments
Seed companiesClauseLefroy Valley Terranova SyngentaSeminisSPS
Plant Pathology teamChrys Akem Elio JovicichGerry Mac ManusKerry-lee Stockdale Dalvinder Lakhesar Paula Boccalatte
Chemical companiesColin Campbell (Chemicals) Pty LtdOrganic Crop Protectants Pty Ltd.Agrichem Mfg. Co.Jaegar Australia Pty LtdNufarmSyngenta Crop Protection Pty Cal Agri, Products LLCBayer Australia Ltd
Agri-Science Queensland,Department of Employment, Economic Development and Innovation
Horticulture Australia Limited
Project VG07127Integrated Management of Foliar Diseases in Vegetable Crops