Download What Lurks in Your Canola Field: Disease Surveys of 2009

What Lurks in Your Canola Field:
Disease Surveys of 2009
Debra McLaren & Anastasia Kubinec
AAFC-Brandon and MAFRI-Carman
Studies / Collaborators
Survey of Canola Diseases in Manitoba
Surveillance and dispersal of Plasmodiophora
brassicae in western Canada
D. McLaren, A. Kubinec, R. Kutcher, S. Strelkov, F.
Dokken, P. Northover, S-F. Hwang, R. Howard
and K. Turkington
Manitoba Team for Canola Survey
• Manitoba Canola Growers Association
• AAFC
– Deb McLaren, Tom Henderson, Danny
Hausermann and Teri Kerley
• MAFRI
– Anastasia Kubinec, Brian Jack, Stephanie Jersak,
Hilmar Johnson, Lionel Kaskiw, Ingrid Kristjanson
and Kristen Phillips
• Canola Council of Canada
– Derwyn Hammond
Canola Fields for Survey in Manitoba
• 140 canola fields in
Manitoba
• 60 of these fields = soil
samples for clubroot
Bruce Barker
Bruce Barker
Red = disease survey + soil sample
Green = disease survey only
In The Field
20 paces
100 paces
100 paces
Sanitation Practices for Canola Survey
• Wear disposable booties and disposable
rubber gloves
• Sterilize soil sampling equipment in bleach
after leaving field but before entering vehicle
• Eliminate transport of infected soil outside of
the sealed soil sample.
• Do not drive into the field
Soil Collection for Clubroot Assessment
• Collect 1 L soil from all 5 points of W
combined
• If entrance to field is obvious, collect soil from
5 points in area limited to the vicinity of this
approach.
• To collect soil, clear away crop residue and
scoop approx. 1 cup soil from top 5-10 cm
• Place in paper bags to air-dry.
Canola Diseases
Sclerotinia Stem Rot
Blackleg
Alternaria Black Spot
Aster Yellows
Fusarium Wilt
Foot Rot
Clubroot
Sclerotinia Stem Rot: Sclerotinia sclerotiorum
Canola Council of Canada
Frayed Stems and Presence of Sclerotia
Premature Ripening & Crop Lodging
Canola Council of Canada
Canola Council of Canada
Rating for Sclerotinia Stem Rot
• Main stem lesions that affected the
entire plant were recorded
separately from any lesion in the
upper branches or pods
Sclerotinia Stem Rot in Manitoba (2009)
Canola Council
Crop Region
Central
No. of
Crops
49
Prevalence (%) Incidence
96
19
East./Interlake
20
100
37
Northwest
23
96
20
Southwest
48
81
7
Province
140
91
18
Sclerotinia in Canola: Previous Years
Year
No. of Crops Prevalence (%)
Incidence
2008
54
94
23
2007
40
80
5
2006
33
39
3
2005
81
40
3
2004
68
72
9
Blackleg: Leptosphaeria maculans
Whitish, round to irregular
lesions on leaves dotted with
pycnidia
Lesions on leaves become
papery and dry
Brown to greyish black lesions,
become sunken cankers ,
girdling the stem
Black lines inside base of stem
Premature plant death
Blackleg
Damage due to blackleg
basal stem cankers
Blackleg on
canola pod
and upper
stem
Blackleg Rating System
• Main stem lesions that affected the entire plant
were recorded separately from any lesion(s) in
the upper branches or pods
• Cankers formed early in the season may girdle
the stem (virulent strain – L. maculans)
• Weakly virulent strain (L. biglobosa) also
causes stem lesions but superficial, nongirdling and occur late in the season so don’t
affect yield
Blackleg in Manitoba Canola Fields (2009)
CCC
Basal Cankers
Crop
Region
Upper Stem Lesions
Percent
Percent
Prevalence Incidence Prevalence
Incidence
Central
76
8
76
5
East./Inter.
75
4
60
2
Northwest
22
2
43
7
Southwest
44
2
40
1
Province
56
4
56
4
Blackleg in Canola: Previous Years
CCC
Basal Cankers
Crop
Region
Upper Stem Lesions
Percent
Percent
Prevalence Incidence Prevalence
Incidence
2008
17
3
54
7
2007
52
2
65
7
2006
39
7
61
5
2005
60
4
65
6
2004
32
6
35
5
Alternaria Black Spot
Canola Council of Canada
Canola Council of Canada
•Brown to black small, round spots on
pods and stems
•As disease progresses, spots
become black to gray with black
border
•Leaves die and drop off
•Pods become dry and sunken and
split prematurely
Alternaria Black Spot
Canola Council of Canada
Rating Scale for Alternaria Black Spot
Alternaria black spot on canola
Conn et al. 1990
Alternaria Black Spot
No. of
Crops
Prevalence (%)
Disease
Severity
Central
49
47
<1
East./Interlake
20
85
<1
Northwest
23
22
<1
Southwest
48
23
<1
Province
140
40
<1
Crop Region
* Generally a 1% infection of pods or stems translates into a 1% yield loss.
Fusarium Wilt (F. oxysporum f.sp. conglutinans)
Canola Council of Canada
• In some plants,
yellowing &
necrosis affects
one side of stem,
or individual
branches
Healthy
Distinct colour: grey-green with a red-pink cast
Fusarium Wilt
Crop Region
Central
No. of
Crops
49
Prevalence (%) Incidence
2
<1
East./Interlake
20
10
<1
Northwest
23
0
0
Southwest
48
4
<1
Province
140
4
<1
Fusarium Wilt : Previous Years
Crop Region
2008
No. of
Crops
54
Prevalence (%) Incidence
9
1
2007
40
15
<1
2006
33
18
1
2005
81
21
1
2004
68
0
0
Aster Yellows
Diseases of Field Crops in Canada, CPS
Aster Yellows
•Transmitted by aster
leafhoppers
•Malformation of the floral parts
•Round to oval blue-greenish,
hollow bladder like formations
Aster Yellows
Crop Region
No. of
Crops
Prevalence (%) Incidence
Central
49
14
<1
East./Interlake
20
20
<1
Northwest
23
13
<1
Southwest
48
15
<1
Province
140
15
<1
Diseases of Field Crops in Canada
Foot Rot
• Early symptoms of light
brown lesions on roots
(taproot and/or main
lateral roots) below soil
line
• Lesions enlarge, leaving
a “stubby root
• Plants ripen prematurely
Foot Rot
• Foot rot was observed
in 2% of canola fields
• Disease incidence was
<1% in Central, E/I and
NW regions.
• No foot rot observed in
SW region.
Clubroot : Plasmodiophora brassicae
Sowiak
Turkington
Clubroot
Healthy
Root
Young Root
Galls
Strelkov
Range of Clubroot Symptom Severity
Healthy
Sowiak
Diseases of Field Crops in Canada
Turkington
Decaying
Clubroot
Galls
Disintegration and
spore release
Why is Clubroot of Concern?
• Serious disease of canola, mustard and other
crops in the cabbage family
• Spreads through resting spores in soil
• Resting spores are extremely long lived
• This can be problematic under tight rotations
• Infestations near 20% cause yield loss of
10%
• Yield and quality (oil content) of the seed are
reduced
Clubroot – Life Cycle of Pathogen
Clubroot Status (Oct. 2009)
•
•
•
Clubroot confirmed in 454
fields since 2003
224 fields visited & 49 new
cases identified in 2009
17 municipalities & City of
Edmonton
– Additional cases suspected
but not confirmed
•
•
Presence of P. brassicae
inoculum also confirmed in
Saskatchewan (1 field in 2008)
Presence in Manitoba in one
canola field in 2005.
What is being done about Clubroot?
• April 2007 – clubroot added as a declared
pest to Alberta’s Agricultural Pest Act.
• June 2009 – clubroot declared a pest in SK
under The Pest Control Act.
• Not a legislated pest in Manitoba yet but this
is in progress
• Required to take steps to destroy, control and
prevent spread of clubroot.
Potential for Clubroot Infestations – Climex Modelling
Turkington, Olfert & Weiss
Clubroot – Management Strategies
• Use long rotations between crops – 4 yrs or more
• Practice good sanitation to restrict movement of
contaminated soil
• Soil conservation practices to reduce erosion
• Scout regularly to ID causes of wilting, stunting,
yellowing and premature ripening
• Avoid common untreated seed because ‘earth tag’
on seed from infested fields could introduce resting
spores to clean fields.
• Risk of spreading clubroot through contaminated
seed is much less than through transporting
contaminated soil on field equipment.
Summary
•
Clubroot
– Alberta: New cases of clubroot continue to be identified
– Saskatchewan: One case of clubroot 2008; no symptoms in 2009; soil
sample results pending
– Manitoba: No clubroot symptoms in 2009; soil samples
•
Sclerotinia:
– Similar levels in past few years
•
Blackleg:
– prevalence of basal cankers increased; that of stem cankers relatively the
same.
•
Fusarium wilt:
– prevalence reduced over years
•
Survey of Manitoba canola fields:
– will continue as a collaboration between AAFC, MAFRI, MCGA, and CCC
Acknowledgements: Technical Staff at AAFC-Brandon
Tom Henderson
Teri Kerley
Danny Hausermann