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
Canola Council of Canada Sclerotinia Stem Rot: Sclerotinia sclerotiorum
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 No. of Crops Prevalence (%) Incidence Central 49 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 Upper Stem Lesions Crop Region Percent Prevalence Incidence Percent 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 Upper Stem Lesions Crop Region Percent Prevalence Incidence Percent 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 Crop Region 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 * 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 No. of Crops Prevalence (%) Incidence Central 49 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 No. of Crops Prevalence (%) Incidence 2008 54 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
Foot Rot Diseases of Field Crops in Canada 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
Disintegration and spore release Decaying Clubroot Galls
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 Danny Hausermann Teri Kerley