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  • Muck Vegetable Cultivar Trial & Research Report

    2009

    M.R. McDonald S. Janse K. Vander Kooi

    Office of Research & Muck Crops Dept. of Plant Agriculture Research Station Report No. 59 Kettleby, Ontario

  • Research and Cultivar Trial Report for 2009

    University of Guelph Office of Research &

    Department of Plant Agriculture Muck Crops Research Station

    1125 Woodchoppers Lane

    R.R. # 1 Kettleby, Ontario L0G 1J0 Phone (905) 775-3783 Fax: (905) 775-4546

    www.uoguelph.ca/muckcrop/

    INDEX

    Page Index .............................................................................................................................................................................. 1-3 Staff .................................................................................................................................................................................. 4 Co-operators ..................................................................................................................................................................... 5 Seed Sources 2009 ......................................................................................................................................................... 6 Legend of Seed Sources ................................................................................................................................................... 7 Introduction and Acknowledgements ............................................................................................................................... 8 Weather Data: Precipitation .............................................................................................................. 10-11 Mean Temperature .................................................................................................... 12-13 Extreme Temperature ................................................................................................ 14-15 Growing Degree Days .................................................................................................... 16 RESEARCH PROJECTS Carrots 1. Comparison of Various Insecticide Seed Treatments and Foliar Sprays for Control of Damage by Carrot Rust Fly & Carrot Weevil in Carrots, 2009 ................................................................................................. 18-20 2. Evaluation of Post-Harvest Fungicide Treatments to Control Sclerotinia Sclerotiorum in Stored Carrots, 2008-2009 ................................................................................................................................................... 21-23 3. Comparison of Various Carrot Cultivars Inoculated with Sclerotinia Sclerotiorum for Resistance to Sclerotinia Rot of Carrots, 2008-2009 ......................................................................................................... 24-25 4. Evaluation of Fungicides on Carrot Inoculated with Sclerotinia Sclerotiorum for Sclerotinia Rot of Carrot Disease Control, 2008-2009 ........................................................................................................................ 26-27 5. Evaluation of Ranman for Control of Cavity Spot on Carrots, 2009 .................................................................. 28-29 6. Evaluation of Polyversum (Pythium Oligandrum) for Management of Cavity Spot on Carrots, 2009 .............. 30-31 7. Evaluation of Various Coloured Carrots for Susceptibility to Cavity Spot, 2009 .............................................. 32-33 8. Evaluation of Various Carrot Cultivars for Susceptibility to Cavity Spot, 2009 ................................................ 34-35 9. Detection of Ascospores of Sclerotinia Sclerotiorum Correlates Among Sites Within a Region and to Disease Incidence ........................................................................................................................................ 36-37 10. Detection of Ascospores of Sclerotinia Sclerotiorum Provides Accurate Timing for Managing Sclerotinia Rot of Carrot ...................................................................................................................................................... 38-39 11. Influence of Freezing Temperatures and the Contans WG Biological Control Product on Germination of Sclerotia of Sclerotiorum in Carrot ............................................................................................................. 40-41 /continued

  • RESEARCH PROJECTS continued Page 12. Herbicide Tolerance in Carrots and Celery, 2009 .............................................................................................. 42-43 13. Evaluation of Different Coloured Carrots for Total Phenolic Content and Antioxidant Activity, 2008 ............ 44-45 14. Effect of Nitrogen Rate and Number of Fungicides Applications on Carrot Total Phenolic Content and Total Antioxidant Activity, 2008 .......................................................................................................................... 46-47 Cole Crops 15. Effect of Seeding Date & Ranman Application on Clubroot of Asian Vegetables, 2009 .................................. 48-50 16. Efficacy of Biofungicides & Fungicides on Clubroot in Shanghai Pak Choy Grown in Controlled Environment, 2009 ...................................................................................................................................... 51-53 17. Evaluation of Biofungicides & Fungicides for Clubroot Control on Napa Cabbage, 2009 ................................ 54-55 18. Evaluation of Biofungicides & Fungicides for Clubroot Control on Shanghai Pak Choi, 2009 ........................ 56-57 19. Effect of Temperature on Clubroot in Brassica Crops Grown in a Controlled Environment, 2009 ................... 58-59 20. Host Screening of Plasmodiophora Brassicae for Resistance and Susceptibility, 2009 .................................... 60-61 21. Comparison of Various Green & Napa Cabbage Cultivars for Resistance & Susceptibility to Clubroot, 2009 ............................................................................................................................................. 62-63 22. Evaluation of Phosphorus Requirements for Asian Vegetables Grown on Organic (Muck) Soil, 2009 ............ 64-65 Onion 23. Identification of Efficient Sprayer Application Tools to Maximize Onion Thrips Control, 2009 ...................... 66-67 24. Comparison of Products to Control Onion Thrips in Small Scale Plot Trials, 2009 .......................................... 68-69 25. Efficacy of Insecticides to Control Onion Thrips in Large Plot Field Trials, 2009 ............................................ 70-71 26. Evaluation of Various Seed Treatments for Control of Onion Smut in Yellow Cooking Onions, 2009 ............ 72-73 27. Comparison of Various Onion Cultivars for Resistance to Downy Mildew (Peronospora Destructor) in Onions, 2009 ........................................................................................................................................... 74-75 28. Comparison of Various Rates of Experimental Fungicides for Control of Downy Mildew (Peronospora ................. destructor) in Onions, 2009 ......................................................................................................................... 76-77 29. Comparison of Various Fungicides for Control of Downy Mildew (Peronospora Destructor) in Onions, 2009 ........................................................................................................................................... 78-79 30. Efficacy of Various Spray Nozzles & Angles for the Control of Botrytis Leaf Blight on Onions, 2009 ........... 80-81 31. Chateau for Weed Control in Dry Bulb Onions, 2009........................................................................................ 82-83 32. Onion Herbicide Performance, 2009 .................................................................................................................. 84-85 33. Evaluation of Crop Nutrition on Onion Total Phenolic Content and Total Antioxidant Activity, 2008 ............ 86-87 34. Evaluation of Phosphorus Requirements on Organic (Muck) Soil, 2009 ........................................................... 88-90 35. Phosphorus Management in Organic (Muck) Soil, 2009 ................................................................................... 91-95 Miscellaneous 36. Evaluation of Various Biofungicides for the Control of Clubroot on Canola, 2009 .......................................... 96-97 37. Potential for Seed Transmission of Plasmodiophora Brassicae Inoculum on Canola Seeds, 2009 ......................... 98 38. Efficacy of Scholar 230C on Fusarium Rot of Garlic, 2008-2009 ................................................................... 99-101 39. Evaluation of Polyversum for Control of Sclerotinia Drop on Inoculated Lettuce, 2009 .............................. 102-103 40. Evaluation of Polyversum (Pythium Oligandrum) for Control of Downy Mildew (Bremia Lactucae) on Lettuce, 2009 ........................................................................................................................................... 104-106 41. Evaluation of Biological Fungicide for Control of White Mould on Inoculated Snap Beans, 2009 ...................... 107 42. Sensitivity of Field Isolates of Ascochyta Rabiei to Strobilurin Fungicides in 2007-2008 ............................ 108-112 43. Tolerance of Leeks to Herbicides, 2009 ......................................................................................................... 113-114 44. Efficacy of Flumioxazin on Muck Soil, 2009 ................................................................................................ 115-118 45. Evaluation of Phosphorus Requirements for Celery Grown on Organic (Muck) Soil, 2009 ......................... 119-120 /continued

  • CULTIVAR TRIALS Page Carrot -Seasonal Summary ........................................................................ 122-123 -Management Procedures ............................................................... 124-127 -Main .............................................................................................. 128-135 -Main Evaluation Notes ................................................................. 136-139 -Long Term Averages .................................................................... 140-141 -Adaptation ..................................................................................... 142-144 -Adaptation Evaluation Notes ................................................................ 145 -Storage Trial 2008-2009 ............................................................... 146-147 -Storage Trial Evaluation Notes ..................................................... 148-149 -Long Term Averages Storage ....................................................... 150-151 Onion Yellow -Seasonal Summary ........................................................................ 152-153 -Management Procedures ............................................................... 154-157 -Main ............................................................................................ 158-1666 -Blank Page ............................................................................................ 167 -Main Evaluation Notes ................................................................. 168-171 -Long Term Averages .................................................................... 172-173 -Adaptation ..................................................................................... 174-175 -Adaptation Evaluation Notes ........................................................ 176-177 -Storage Trial 2008-2009 ............................................................... 178-180 -Storage Trial Evaluation Notes ..................................................... 181-183 -Long Term Averages Storage ....................................................... 184-185

  • STAFF - 2009

    UNIVERSITY OF GUELPH

    Office of Research

    &

    Department of Plant Agriculture

    MUCK CROPS RESEARCH STATION

    Shawn Janse Research Station Manager

    Mary Ruth McDonald, Ph.D., P.Ag. Research Scientist

    Kevin Vander Kooi Agricultural Technician

    Michael Tesfaendrias Research Associate

    Laura Riches Research Assistant

    Jessica Levesque Research Assistant

    Derk Hovius Agricultural Worker

    Seasonal Contracts:

    Alexandra Segouin Summer Assistant

    Matthew Southcott Summer Assistant

    Kristina Svirga Summer Assistant

    Bridget Visser Summer Assistant

    Greg Biersteker Summer Experience

    Graduate Students:

    Monica Parker Department of Plant Agriculture

    Kalpana KC Department of Plant Agriculture

    IPM Supervisor: Scouts:

    Michael Tesfaendrias Kyle Adams

    Shannon Richie

  • CO-OPERATING COMPANIES

    Special thanks for supplying seed used in many of the research projects at the Muck Crops

    Research Station.

    Stokes Seed Ltd Jim Robinson

    Bejo/Seedway Jan Van Der Heide & Frank Jonkman

    CO-OPERATING RESEARCH STAFF - EDUCATION/RESEARCH/GOVERNMENT

    Clarence Swanton Dept. of Plant Agriculture, University of Guelph, Ontario, Canada

    Kevin Chandler Dept. of Plant Agriculture, University of Guelph, Ontario, Canada

    Greg Boland Environmental Biology, University of Guelph, Ontario, Canada

    Ivan OHalloran Ridgetown Collage, University of Guelph, Ridgetown, Ontario, Canada

    Donna Speranzini Ontario Ministry of Agriculture, Food & Rural Affairs, Guelph, Ontario

    Jennifer Allen Ontario Ministry of Agriculture, Food & Rural Affairs, Guelph, Ontario

    Christoph Kessel Ontario Ministry of Agriculture, Food & Rural Affairs, Guelph, Ontario

    Bruce Gossen Agriculture & Agri-Food Canada, Saskatoon, Canada

    Gary Peng Agriculture & Agri-Food Canada, Saskatoon, Canada

    Tom Wolf Agriculture & Agri-Food Canada, Saskatoon, Canada

    Alan Taylor Dept. Horticultural Science, Cornell University, New York, U.S.A.

    Phil Simon University of Wisconsin, Madison, Wisconsin, U.S.A.

    Jim Farrar California State University, Fresno, California, U.S.A.

    Mike Walters Lake Simcoe Region Conservation Authority, Newmarket, Ontario

    CO-OPERATING RESEARCH STAFF - INDUSTRY/PRIVATE SECTOR

    Greg Patterson A & L Canada Laboratories Inc, London, Ontario, Canada

    Jeff Holmes Holmes Agro Ltd, Orangeville, Ontario, Canada

    Jim Behm FMC Corp., Philadelphia, Pennsylvania, U.S.A.

    Trevor Kraus BASF Canada, London, Ontario, Canada

    Beth Conner Valent Canada Inc, Guelph, Ontario, Canada

    Martin Bloomberg Nutri Ag Ltd, Toronto, Ontario, Canada

    Mark McMillan Nutri Ag Ltd, Toronto, Ontario, Canada

    Bill McClintock Beta-Biologics Ltd, Toronto, Ontario, Canada

  • SEED SOURCES - 2009 - CULTIVAR TRIALS

    BEJO Bejo Seeds Inc., 1088 Healey Road, Geneva, New York, 14456, U.S.A.

    Tel: (308) 789-4155

    NUN Nunhems, 8850 59th

    Avenue N.E., Brooks, Oregon, 97305, U.S.A.

    Tel: (503) 393-3243

    RZ Rijk Zwaan Export B.V., P.O. Box 40, 2678, 2G Delier, Holland

    Tel: 0174-532300

    Sem Seminis Vegetable Seeds, 2700 Camino Del Sol, Oxnard, California, 93030, U.S.A.

    Tel: (866) 334-1056

    Sol Solar Seeds Inc., Box 1158, Bradford, Ontario, L3Z 2B5, Canada

    Tel: (800) 227-7687

    Sto Stokes Seed Ltd., 296 Collier Rd, Box 10, Thorold, Ontario, L2V 5E9, Canada

    Tel: (800) 396-9238

    Tak American Takii Inc., 301 Natividad Rd., Salinas, California, 93906, U.S.A.

    Tel: (408) 443-4901

    UNF Coop Uniforce, 291 rue Cooperative, Sherrington, Quebec, J0L 2N0, Canada

    Tel: (450) 454-3986

    Vil Vilmorin Inc., 2551 N Dragoon Street # 131, Tucson, Arizona, 85745, U.S.A.

    Tel: (520) 884-0011

    We would like to thank our seed suppliers for the various

    cultivar trial submissions in 2009.

  • LEGEND OF SEED SOURCES

    A&C Abbott & Cobb Inc.

    Aris Aristogenes Inc.

    Asg Asgrow Seed Co.

    BBI Bakker Brothers of Idaho, Inc.

    BEJO Bejo Seeds Inc.

    BO Brinker-Orsetti Seed Co.

    Car Cardinal Seed Co. Inc.

    Chr Chriseed

    Cro Crookham Company

    CS Campbell Soup Co.

    CU Cornell University

    DF Daehnfeldt

    E.J. Erie James Ltd.

    FAIR Fairbanks Selected Seed Co.

    FM Ferry-Morse Seed Co.

    FFS Fred Fuller Seeds

    HM Harris Moran Seeds

    Nor Norseco Inc.

    NUN Nunhems USA Inc

    NZ Nickerson-Zwaan B.V.

    Pal D. Palmer Seed Co. Inc.

    PETO Petoseed Co.

    Pol Polonica International

    Rio Rio Colorado Seeds Inc.

    Rog Rogers Seed

    RS Royal Sluis Inc.

    RZ Rijk Zwaan Export B.V.

    Sak Sakata Seed America Inc.

    SC Seed Science Inc.

    Sham Shamrock Seed Co.

    Sem Seminis Vegetable Seeds

    Sieg Siegers Seed Co.

    Sol Solar Seed Co.

    Sto Stokes Seeds Ltd.

    Sun Sun Seeds

    SW Seedworks

    Swy Seedway Inc.

    Tak American Takii Inc.

    Toz A. L. Tozer Ltd.

    Wis University of Wisconsin

    VDH Vanderhave

    UNF Co-op Uniforce

    Vil Vilmorin Inc.

    ZW Zwaan Seeds, Inc

  • INTRODUCTION AND ACKNOWLEDGMENTS

    The Muck Crops Research Station, as part of the Department of Plant Agriculture and the Office

    of Research, University of Guelph is responsible for conducting and coordinating research

    projects to solve problems in the production of vegetables grown in organic soils. The Ontario

    Root, Bulb & Leafy Vegetable Research and Services Subcommittee representing researchers,

    industry, growers and crop advisors, make recommendations for research on an annual basis.

    In 2009, Muck Crops Research Station staff conducted, and/or co-operated on research projects

    with researchers from the Departments of Environmental Biology and Plant Agriculture at the

    University of Guelph; researchers from OMAFRA, Agriculture and Agri-Food Canada, and

    Cornell, Wisconsin and California State Universities; research departments of the Crop

    Production Chemical Industry, numerous seed companies, and growers.

    This report consists of two sections; the first contains highlights of research projects which were

    conducted in 2009 under the supervision of Professor Dr. Mary Ruth McDonald and other

    researchers at the University of Guelph. The second section contains highlights of various muck

    crops cultivar evaluations in 2009 in field and storage trials, under the supervision of the

    Research Station Manager, Shawn Janse. The results published in this report should be treated as

    a progress report. Some of the chemicals used in the trials are not registered for use on the crops

    they were applied to. Additional trials may be necessary before firm conclusions and

    recommendations can be made.

    The Muck Crops Research Station is an active participant in the training of new researchers on

    muck vegetables through the Graduate Student Program of the University of Guelph. Presently

    the Muck Crops Research Station has five M.Sc. graduate students working on muck vegetables.

    The Muck Crops Research Station continues to conduct research to assist in the future

    registration of chemicals for muck vegetables. Recently, research programs with Dr. Clarence

    Swanton has aided in the registration of Chateau herbicide for onions.

    We would like to take this opportunity to express our sincere appreciation to the staff for their

    efforts in conducting these research projects, cultivar evaluation trials and producing this report.

    Many thanks also to all the co-operating researchers, technicians, industry personal, and growers

    for their continued support and interest in muck crops.

    Mary Ruth McDonald, PhD Shawn Janse

    Associate Professor Research Station Manager

    Department of Plant Agriculture Office of Research

  • Weather

    Data

    2009

  • Month

    Rain Snow Rain Snow Rain Snow Rain Snow Rain Snow Rain Snow

    mm cm mm cm mm cm mm cm mm cm mm cm

    January 22 * 50 * 23 5 20 23 10 17 0 22 4 53

    February 16 * 13 * 10 42 36 30 27 12 0 36 5 9

    March 1 * 23 * 26 1 1 8.5 43 0 0 37 65 6

    April 22 * 0 * 68 10 33 0 77 0 20 7 56 0

    May 65 * 0 * 160 0 85 0 113 0 105 0 108 0

    June 69 0 173 0 63 0 106 0 75 0 50 0

    July 71 0 86 0 60 0 76 0 29 0 102 0

    August 79 0 56 0 32 0 18 0 81 0 104 0

    September 138 0 90 0 53 0 40 0 111 0 25 0

    October 68 0 28 0 111 0 49 0 78 0 26 0

    November 73 9 58 1 78 0 43 30 91 15 54 4

    December 35 2 11 62 27 15 12 22 36 11 43 36

    Annual 657 97 789 121 599 76 614 81 626 128 642 108

    Total Precip.

    LTA = Long Term Average for U of Guelph, Dept. of Plant Agriculture - Kettleby * Data collected from Cookstown,ON

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0. 35 Years (1975-2009)

    2004

    750754695

    1999 2000 2001

    675910

    PRECIPITATION

    2002 2003

    754

  • Month

    Rain Snow Rain Snow Rain Snow Rain Snow Rain Snow Rain Snow

    mm cm mm cm mm cm mm cm mm cm mm cm

    January 20 20 32 17 21 29 27 22 0* 44 19 29

    February 17 34 25 21 6 33 31 56 48* 26 20 24

    March 13 0 15 3 24 10 19 47 56* 5 30 15

    April 74 0 44 2 54 0 44 0 105 0 55 4

    May 14 0 65 0 43 0 56 0 117 0 74 0

    June 63 0 64 0 29 0 68 0 49 0 74 0

    July 33 0 72 0 27 0 137 0 135 0 83 0

    August 56 0 41 0 33 0 62 0 89 0 80 0

    September 53 0 174 0 40 0 81 0 51 0 83 0

    October 41 0 102 0 32 0 54 0 62 0 67 1

    November 87 14 67 0 54 20 30* 13 31 2 55 10

    December 38 34 25 9 22 77 13* 63 46 9 24 28

    Annual 509 102 726 52 385 169 622 201 789 86 663 111

    Total Precip. 823 875 773

    LTA = Long Term Average for U of Guelph, Dept. of Plant Agriculture - Kettleby * Data collected from Egbert, ON

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0. 35 Years (1975-2009)

    2008

    611 554

    2005 2009 LTA

    PRECIPITATION

    2006

    778

    2007

  • Month 1999 2000 2001 2002

    Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min.

    January -4.5 * -12.8 * -1.8 -12.6 -1.3 -9.8 1.6 -5.1 -5.0 -15.1 -6.6 -17.1

    February 0.6 * -8.1 * 0.9 -10.0 -0.4 -9.6 2.0 -7.6 -3.5 -15.2 0.0 -12.2

    March 2.5 * -6.9 * 8.8 -1.4 2.2 -6.0 4.0 -4.9 3.9 -8.9 5.2 -11.7

    April 12.2 * 0.8 * 10.4 0.6 13.2 1.3 10.9 1.8 10.2 -1.3 10.6 0.7

    May 21.8 * 6.4 * 19.0 7.2 20.2 7.6 16.0 3.8 17.1 5.9 18.6 6.3

    June 25.4 12.7 23.2 11.4 25.2 11.4 24.2 12.2 23.9 10.6 22.9 9.6

    July 28.4 15.7 24.2 12.6 25.1 12.6 28.8 14.6 26.4 13.5 25.3 13.2

    August 24.1 12.2 24.8 11.8 27.8 13.3 26.9 12.3 26.9 14.0 23.9 11.8

    September 22.8 9.1 20.4 8.0 21.4 7.9 25.0 10.0 21.6 8.4 23.7 9.6

    October 13.6 2.6 15.8 3.3 14.6 4.3 12.2 2.3 13.5 2.4 14.7 3.5

    0.0

    November 9.0 0.4 6.5 -1.9 10.9 1.6 5.4 -1.6 7.7 0.1 8.5 -0.3

    December 2.3 -6.2 -3.9 -14.0 4.1 -3.2 0.8 -7.7 1.9 -5.4 8.5 -0.3

    Mean 10.5 * 3.9 * 12.4 1.3 13.6 2.6 13.1 2.5 12.1 0.7 12.9 1.1

    LTA = Long Term Average for U of Guelph, Dept. of Plant Agriculture - Kettleby * Data collected from Cookstown, ON

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0. 35 Years (1975-2009)

    MEAN TEMPERATURE (C)

    2003 2004

  • Month LTA

    Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min.

    January -3.4 -13.7 2.9 -4.0 -0.4 -9.3 0.2 -7.4 -6.2* -16.2* -2.7 -11.3

    February 1.8 -9.1 -1.8 -10.5 -5.2 -14.2 -2.1 -10.7 -0.8* -10.5* -1.4 -10.5

    March 2.8 -5.9 4.2 -4.5 4.4 -5.2 -0.8 -9.0 4.5* -6.3* 2.9 -5.6

    April 12.5 0.7 13.2 1.4 10.1 0.5 14.4 2.7 12.7 0.8 11.2 1.1

    May 17.8 3.7 19.9 7.6 20.7 4.5 17.0 4.4 18.7 5.5 18.7 6.6

    June 27.7 14.7 24.5 12.3 26.3 11.3 24.8 13.6 22.3 10.2 23.9 11.4

    July 28.8 14.7 28.2 15.5 26.0 12.4 26.6 14.1 23.6 11.7 26.3 13.9

    August 26.8 13.0 25.8 12.5 26.7 12.8 25.1 11.0 25.2 13.0 25.3 12.8

    September 24.1 9.4 19.3 9.3 23.8 8.7 21.7 8.2 21.9 7.5 20.8 8.9

    October 14.8 5.2 12.8 3.0 18.5 6.5 13.2 1.5 11.9 2.8 13.5 3.6

    November 9.0 -0.6 8.6 1.3 5.5 -3.4 5.3* -3.4 * 9.7 -0.4 6.5 -0.9

    December -1.7 -8.1 4.6 -1.8 -1.0 -8.6 -1.7* -9.9 * 0.3 -6.0 0.2 -7.0

    Mean 13.4 2.0 13.5 3.5 13.0 1.3 12.0 1.3 12.0 1.0 12.1 1.9

    LTA = Long Term Average for U of Guelph, Dept. of Plant Agriculture - Kettleby * Data collected from Egbert, ON

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0. 35 Years (1975-2009)

    2009

    MEAN TEMPERATURE (C)

    20072005 2006 2008

  • Month H L H L H L H L H L H L

    January 12.1 -28.1 4.0 -27.3 10.4 -16.4 4.3 -28.8 12.4 -31.7 15.8 -30.2

    February 14.4 -25.0 7.7 -24.5 12.9 -20.7 6.2 -29.3 7.9 -25.2 6.5 -17.4

    March 23.9 -8.4 8.6 -18.9 17.3 -12.5 16.9 -27.7 16.8 -11.7 16.0 -14.2

    April 22.1 -6.6 25.5 -4.3 29.2 -9.7 26.9 -12.8 23.7 -8.1 27.4 -3.3

    May 30.0 -1.8 29.6 -1.4 28.1 -1.5 23.7 -1.4 29.3 -1.4 26.2 -1.6

    June 31.7 5.0 33.0 3.1 31.9 2.7 34.6 3.2 32.4 2.4 35.0 6.1

    July 27.7 5.6 32.2 5.0 34.4 6.9 33.4 7.4 30.1 5.2 35.0 7.1

    August 29.8 3.2 36.3 7.2 33.4 5.0 33.0 5.9 28.8 3.4 32.8 7.0

    September 30.8 -1.8 30.6 1.3 34.4 0.5 28.5 1.3 29.0 1.7 31.9 1.6

    October 23.6 -5.1 26.7 -4.4 29.0 -5.4 26.6 -2.0 26.5 -2.9 28.8 -2.7

    November 19.4 -14.9 18.3 -3.6 16.1 -8.4 17.7 -8.1 13.6 -6.5 18.8 -14.4

    December 6.0 -25.1 16.8 -13.8 7.7 -20.0 8.8 -17.2 10.1 -28.4 4.2 -22.1

    Annual 31.7 -28.1 36.3 -27.3 34.4 -20.7 34.6 -29.3 32.4 -31.7 35.0 -30.2

    High & Low

    Extreme Temperatures for U of Guelph, Dept. of Plant Agriculture - Kettleby

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0. 35 Years (1975-2009)

    2004 20052001

    EXTREME TEMPERATURE (C)

    2000 2002 2003

  • EXTREME TEMPERATURES

    Month H L H L H L H L H Year L Year

    January 11.4 -13.1 11.1 -25.5 13.8 -26.7 1.9 * -30.3 * 15.8 2005 -36.0 1977

    February 6.6 -22.3 3.2 -23.4 6.6 -20.9 8.9 * -2.7 * 14.5 1984 -33.0 1979

    March 18.9 -14.1 20.8 -24.5 8.1 -25.5 15.3 * -18.9 * 24.0 1986 -29.0 1984

    April 22.6 -5.7 24.3 -8.0 25.7 -2.6 27.3 -5.3 30.0 1990 -14.0 1983

    May 34.6 -2.8 32.6 -2.6 27.4 -2.6 29.9 -1.8 34.6 2006 -4.0 1983

    June 33.2 6.3 33.4 3.7 33.6 8.1 32.2 1.7 35.5 1988 -2.0 1977

    July 33.3 9.2 32.9 5.1 31.6 6.4 27.6 4.9 36.0 1988 2.5 1984

    August 36.0 4.9 34.7 4.2 33.8 3.7 31.3 4.5 36.3 2001 0.5 1982

    September 27.1 0.7 33.5 0.9 31.1 1.8 26.6 -0.7 34.4 2002 -6.5 1991

    October 25.5 -1.4 30.0 -1.4 27.3 -4.9 18.2 -6.1 30.0 89 & 07 -9.0 1975

    November 15.4 -3.4 14.3 -16.2 20.2 * 17.5 * 18.8 -7.2 24.0 1990 -22.0 1977

    December 10.9 -13.2 6.5 -23.0 8.2 * -20.5 * 9.8 -15.7 20.0 1982 -31.5 1980

    Annual 36.0 -22.3 34.7 -25.5 33.6 -26.7 32.2 -30.3 36.3 -36.0

    High & Low

    Extreme Temperatures for U of Guelph, Dept. of Plant Agriculture - Kettleby * Data collected from Egbert, ON

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0. 35 Years (1975-2009)

    20082007

    EXTREME TEMPERATURE (C)

    20092006

  • Month 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 LTA

    January 0* 0 0 1 0 3 3 4 6 13 0* 1

    February 0* 8 0 2 0 0 0 0 0 0 1* 1

    March 7* 31 0 7 17 19 8 14 23 0 7* 13

    April 60* 57 81 99 67 57 58 98 73 147 84 77

    May 284* 251 276 156 202 233 182 226 205 178 220 230

    June 421 369 378 396 368 318 487 401 405 427 338 379

    July 528 417 389 518 463 442 519 523 439 477 391 466

    August 412 413 395 452 477 397 462 439 457 404 436 432

    September 329 276 247 375 300 349 352 279 337 299 291 294

    October 103 147 147 106 100 126 154 101 233 95 72 123

    November 55 30 61 27 29 25 59 42 11 37* 29 31

    December 11 0 19 0 2 0 0 6 0 0* 0 3

    Annual 1859* 1999 1993 2139 2025 1969 2284 2133 2189 2077* 1869* 2050

    LTA = Long Term Average for U of Guelph, Dept. of Plant Agriculture - Kettleby * Data collected from Cookstown 1999, Egbert 2008, 2009)

    1125 Woodchoppers Lane, R.R. #1, Kettleby, ON, L0G 1J0 35 Years (1975-2009)

    GROWING DEGREE DAYS (5C Base)

  • Research

    Reports

    2009

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang.) cv. Cellobunch PESTS: Carrot rust fly (Psila rosae (Fabricius)) Carrot weevil (Listronotus oregonensis (LeConte)) AUTHORS: MCDONALD MR1, VANDER KOOI K1 & TAYLOR A2 1 University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station 2 Cornell University, Dept. of Horticultural Science, New York State Agricultural Experiment Station TITLE: COMPARISON OF VARIOUS INSECTICIDE SEED TREATMENTS AND

    FOLIAR SPRAYS FOR CONTROL OF DAMAGE BY CARROT RUST FLY AND CARROT WEEVIL IN CARROTS, 2009

    MATERIALS: ENTRUST (spinosad 80%), CRUISER (thiamethoxam 47.6%), SEPRESTO 75WS (clothianidin 56.25%, imidacloprid 18.75%), THIRAM 42S (thiram 42%), MOVENTO 240SC (spirotetramat 240 g/L), RIPCORD 400EC (cypermethrin 407 g/L), PERMA-GUARD FOSSIL SHELL FLOUR (100% diatomaceous earth) METHODS: The trial was conducted at the Muck Crops Research Station, Holland Marsh, Ontario, in organic soil (pH 6.5, organic matter 70.3%). Carrots were direct seeded (75-80 seeds/m) onto raised beds using a push V-belt seeder on 28 May. A randomized complete block arrangement with four replicates per treatment was used. Each experimental unit consisted of two rows, 86 cm apart and 5 m in length. Treatments were: ENTRUST at 3.75 and 7.5 g ai, CRUISER at 2.5 and 3.75 g ai, SEPRESTO 75WS at 5.63 and 11.25 g ai, MOVENTO at 375 mL/ha, RIPCORD at 175 mL/ha, PERMA-GUARD at 1.0 kg/ha, ENTRUST at 7.5 g ai + MOVENTO at 375 mL/ha and CRUISER at 3.75 g ai + MOVENTO at 375 mL/ha. An untreated check was also included. All seed treatments were expressed as g ai/100 g of seeds and all treatments included 250 mg ai THIRAM (fungicide) per 100 g of seed. Foliar sprays were applied on 13, 28 August, 8 and 23 September and when combined with a seed treatment, MOVENTO was applied on 8 and 23 September (after the first assessment) using a CO2 backpack sprayer equipped with a single TeeJet 1104 nozzle calibrated to deliver 500 L/ha at 250 kPa. On 2 September, carrots in a 1.16 m section of row were pulled, washed by hand, assessed visually for carrot rust fly and carrot weevil and numbers recorded. On 22 October carrots in a 1.16 m section of row were taken from each replicate and placed in storage. On 8 January, 2010, carrots were removed from storage and washed in a small drum washer to reveal damage caused by both carrot rust fly and carrot weevil. Assessments were made by inspecting each carrot for damage and calculating the percentage of carrots damaged by either pest. The air temperatures in 2009 were below the long term (10 year) average for June (16.5C), July (17.9C) and October (7.3C), and average for May (12.6C), August (19.4C) and September (14.9C). The long term (10 year) average temperatures were: May 12.1C, June 18.2C, July 19.9C, August 19.3C, September 15.5C and October 8.9C. Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for May (117 mm), July (135 mm), August (89 mm) and October (62 mm). The long term (10 year) rainfall averages were: May 86 mm, June 74 mm, July 76 mm, August 57 mm, September 72 mm and October 59 mm. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix V.9. Means separation was obtained using Fishers Protected LSD test at P = 0.05 level of significance. RESULTS: As presented in Tables 1 & 2 CONCLUSIONS: Significant differences were found among the treatments at the 2 September assessment in the percentage of carrots damaged by both carrot weevil and rust fly (Table 1). Total insect damage was high (39.4% in the check plots) in the trial. Total damage in the best treatment was 11%, a reduction in damage of 28%. Carrots treated with PERMA-GUARD or RIPCORD had significantly less

  • total insect damage than carrots grown from seeds treated with ENTRUST 7.5 or SEPRESTO at 5.6 g ai/100 seeds. There were no significant differences in the percentage of carrot rust fly or carrot weevil damage when assessed individually among the treatments (Table 1). There were significant differences in marketable yield at the 8 January assessment date. Carrots treated with foliar sprays RIPCORD, PERMA-GUARD, or MOVENTO or grown from seeds treated with SEPRESTO at 11.25 g ai/100 seeds had a significantly higher marketable yield than carrots grown from seeds treated with CRUISER at 3.75 g ai or ENTRUST at 7.5 g ai and also receiving two foliar applications of MOVENTO, or carrots grown from seeds treated with CRUISER at 2.5 or 3.75 g ai per 100 seeds. There were no significant differences among the treatments at the 8 January assessment in carrot rust fly or carrot weevil damage (Table 2). Table 1. Insect damage assessed on 2 September, in carrots treated with insecticide seed treatments and foliar applications, grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009.

    Treatment Treatment Type Rate % Total Insect

    Damage % Carrot Weevil

    Damage % Carrot Rust Fly Damage

    PERMA-GUARD foliar 1 kg/ha 10.9 a1 9.7 ns2 1.2 ns

    RIPCORD foliar 175 mL/ha 14.6 ab 11.5 3.1

    SEPRESTO seed 11.25 g ai/100 seeds 20.0 abc 19.3 0.7

    CRUISER seed 3.75 g ai/100 seeds 20.3 abc 18.0 2.2

    MOVENTO foliar 375 mL/ha 22.7 abc 21.8 0.9

    ENTRUST seed 3.75 g ai/100 seeds 24.4 bcd 20.8 3.5

    CRUISER seed 2.5 g ai/100 seeds 24.7 bcd 23.9 0.8

    Check -- -- 26.3 bcd 25.1 1.2

    ENTRUST seed 7.5 g ai/100 seeds 30.0 cd 24.8 5.2

    SEPRESTO seed 5.6 g ai/100 seeds 36.4 d 31.1 5.3 1 Numbers in a column followed by the same letter are not significantly different at P = 0.05, Fishers Protected LSD test. 2 Not significantly different, P = 0.05 Fishers Protected LSD Test

  • Table 2. Effects of seed treatments and insecticide foliar spray on damage to carrots by carrot rust fly and carrot weevil, Holland Marsh, Ontario 2009.

    Treatment Rate % Total Insect

    Damage

    % Carrot Rust Fly Damage

    % Carrot Weevil Damage

    Marketable Yield (t/ha)

    RIPCORD 175 mL/ha 21.3 ns1 8.1 ns 13.6 ns 89.9 a2

    PERMA-GUARD 1 kg/ha 24.7 8.7 16.0 85.4 ab

    SEPRESTO 11.25 g ai/100 seeds 26.3 9.5 16.8 75.7 abc

    SEPRESTO 5.6 g ai/100 seeds 29.7 11.0 18.6 65.5 bcd

    ENTRUST 7.5 g ai/100 seeds 39.3 20.7 22.0 56.1 cd

    CRUISER + MOVENTO3 3.75 g ai/100 seeds 30.5 8.5 22.0 52.0 d

    ENTRUST 3.75 g ai/100 seeds 34.3 15.1 22.2 54.6 cd

    MOVENTO 375 mL/ha 34.5 12.9 23.9 77.0 abc

    CRUISER 2.5 g ai/100 seeds 34.2 12.2 24.8 51.3 d

    CRUISER 3.75 g ai/100 seeds 34.0 9.8 26.3 47.3 d

    ENTRUST + MOVENTO3 7.5 g ai/100 seeds 40.1 10.7 30.5 50.5 d

    Check -- 42.5 12.7 32.0 57.2 cd 1 Not significantly different, P = 0.05 Fishers Protected LSD Test 2 Numbers in a column followed by the same letter are not significantly different at P = 0.05, Fishers Protected LSD test. 3 Seed treatments plus two foliar applications of MOVENTO at 375 mL/ha applied on 8 and 23 September Funding for this project was supplied by the OMAFRA/University of Guelph Sustainable Production Systems Program and the New York State Agricultural Experiment Station, Cornell University provided support to conduct field research as part of a larger US project on new chemistry seed treatments.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang.) cv. Envy PEST: Sclerotinia rot of carrot, (Sclerotinia sclerotiorum (Lib.) de Bary) AUTHORS: MCDONALD MR and VANDER KOOI K

    Muck Crops Research Station, Dept. of Plant Agriculture, University of Guelph TITLE: EVALUATION OF POST-HARVEST FUNGICIDE TREATMENTS TO

    CONTROL SCLEROTINIA SCLEROTIORUM IN STORED CARROTS, 2008-09 MATERIALS: SCHOLAR (fludioxinil 50%), MERTECT (thiabendazole 50%) METHODS: Carrots, cv. Envy, grown in muck soil at Muck Crops Research Station, Holland Marsh, Ontario, were washed and graded on 10 November 2008 at a commercial packing facility. Each experimental unit consisted of one plastic bag containing 30 carrots. Treatments were: SCHOLAR at the rates of 65.6, 131.2 and 250.6 mL, MERTECT at 108.4 mL and SCHOLAR + MERTECT at 131.2 mL + 108 mL, respectively, per100 L of water used as dip treatments, and Scholar at the rate of 131.2 mL/100 L of water applied as a drench. Untreated non-inoculated and inoculated checks were also included. Sclerotinia sclerotiorum taken from a diseased carrot was plated onto PDA amended with Streptomycin sulphate and allowed to grow from one week until mycelia filled the plate. Carrots were surface sterilized with 1% sodium hypochloride and were wounded then inoculated with 5 mm plugs taken from the edge of actively growing cultures, 3 plugs per carrot and kept at 21C for 10 days. On 17 November 2008, carrots in mesh bags were immersed for 30 seconds for dip treatments. The drench application was applied by evenly spraying spread-out carrots using a CO2 backpack sprayer equipped with an 8002 TeeJet nozzle. Carrots were allowed to dry, and then packed, 30 carrots per bag, into a plastic 35 x 70 cm (11.34 kg size) commercial carrot bag. An inoculated carrot was placed in the middle of each bag for all inoculated treatments. Carrot bags were placed in plastic tote boxes, stacked on pallets and stored in Filacell storage at 1 C, 95% RH. A complete randomized arrangement with four replicates per treatment was used. Four replicate bags from each treatment were assessed each month of the 6 month storage period. Carrots were assessed monthly for sclerotinia rot and sorted into classes based on a scale of 0 to 6 based on extent of visible mycelial colonization of the carrots where 0 = no rot, 1 = 1 - 5% rot, 2 = 6 10% rot, 3 = 11 25% rot, 4 = 26 50% rot, 5 = 51 75% rot and 6 = 76 - 100% rot on 16 December 2008, 16 January, 13 February, 17 March, 16 April and 14 May 2009. Numbers of carrots in each class were recorded and carrots were weighed. Percent diseased was calculated based on numbers of carrots diseased and disease severity (DSI) was calculated using the following equation:

    DSI = [(rating class)(no. of carrots in each rating class)] x 100 (total no. of carrots rated)(no. classes 1) Data were analysed using the General Analysis of Variance function of the Linear Models section of Statistix V.9. Means separation was obtained using Tukeys HSD test at P = 0.05 level of significance. RESULTS: Disease pressure increased over the six month storage period and significant differences were found among the treatments at the March through May assessments. At all assessment dates there was higher disease incidence on the inoculated untreated check than the non-inoculated untreated check, demonstrating that the inoculation technique was effective (Table 1). At the March assessment, carrots treated with a dip application of any rate of SCHOLAR or SCHOLAR + MERTECT had a significantly lower percent disease and disease severity index (DSI) than the inoculated, untreated check. At the April assessment, carrots treated with a dip application of any rate of SCHOLAR or SCHOLAR + MERTECT had a significantly lower percent disease than the inoculated untreated check, and carrots treated with a dip application of any rate of SCHOLAR, SCHOLAR + MERTECT or the SCHOLAR drench had a significantly lower DSI than the inoculated check. At the May assessment, carrots dipped in SCHOLAR at 250.3 and 131.2 mL/100 L water had a significantly lower percent disease than carrots treated with a drench application of SCHOLAR, a dip application of MERTECT and the

  • inoculated check. Carrots treated with a dip application of SCHOLAR at any rate or the SCHOLAR + Mertect combination had a significantly lower DSI than carrots treated with MERTECT alone. There was no significant difference in percent disease or disease severity between carrots treated with the MERTECT dip and untreated, inoculated carrots (Tables 1 & 2). Overall disease incidence in the inoculated check was significantly higher than the non-inoculated check at every assessment. Disease incidence in the inoculated check increased steadily over the six month trial period to a maximum of 74.2% (Table 1). CONCLUSIONS: MERTECT applied as a dip at a rate of 108.4 mL/100L was not effective in reducing Sclerotinia sclerotiorum on carrots. Disease incidence and severity were always statistically equivalent to the untreated inoculated check. In the March, April and May assessments there were significant differences among fungicide treatments and all rates of SCHOLAR applied as a dip effectively reduced disease incidence and severity. There was no advantage to adding MERTECT with SCHOLAR. SCHOLAR applied as a drench reduced disease incidence and severity, as compared to the inoculated untreated check, in the April and May assessments, but not in the earlier assessments. Table 1. Percentage of Sclerotinia sclerotiorum infection of carrot treated with SCHOLAR, inoculated with S. sclerotiorum and stored for various lengths of time in Filacell storage at Muck Crops Research Station, Holland Marsh, Ontario, 2008-09.

    Treatment Rate (mL/100L) Application

    Method % Disease

    Dec Jan Feb Mar Apr May

    Non inoculated -- -- 0.0 a1 0.0 a 0.0 a 0.0 a 0.8 a 5.8 a

    SCHOLAR 250.3 dip 13.3 ab 13.3 ab 24.2 b 18.3 ab 26.7 ab 20.8 a

    SCHOLAR 131.2 dip 8.3 ab 11.7 ab 16.7 ab 19.2 ab 21.7 ab 20.8 a

    SCHOLAR 65.6 dip 8.3 ab 15.8 ab 12.5 ab 13.3 ab 13.3 ab 25.8 ab SCHOLAR + MERTECT

    131.2 + 108.4 dip 6.7 ab 9.2 ab 20.8 ab 17.5 ab 20.8 ab 25.8 ab

    SCHOLAR 131.2 drench 19.2 b 26.7 b 30.8 b 36.7 bc 32.5 b 45.8 bc

    MERTECT 108.4 dip 12.5 ab 13.3 ab 25.8 b 40.8 bc 40.8 bc 65.8 cd

    Inoculated -- -- 16.7 b 27.5 b 30.0 b 54.2 c 65.8 c 74.2 d 1 Numbers in a column followed by the same letter were not significantly different at P = 0.05, Tukeys test.

  • Table 2. Disease severity index1 of Sclerotinia sclerotiorum infection of various carrot treatments after various lengths of time in Filacell storage at Muck Crops Research Station, Holland Marsh, Ontario, 2008-09.

    Treatment Rate (mL/100L) Application

    Method DSI1,2

    Dec Jan Feb Mar Apr May

    Non inoculated -- -- 0.0 a3 0.0 ns4 0.0 a 0.0 a 0.1 a 1.0 a

    SCHOLAR 250.3 dip 2.6 ab 4.0 9.6 ab 5.6 a 9.0 ab 8.3 ab

    SCHOLAR 131.2 dip 1.8 ab 4.6 5.3 ab 5.3 a 7.5 ab 8.6 ab

    SCHOLAR 65.6 dip 1.5 a 7.8 3.5 ab 3.2 a 3.8 ab 11.3 ab SCHOLAR + MERTECT

    131.2 + 108.4 dip 1.4 a 2.6 8.8 ab 5.0 a 6.9 ab 11.8 ab

    SCHOLAR 131.2 drench 5.8 b 9.4 15.1 a 15.4 ab 16.1 ab 25.8 bc

    MERTECT 108.4 dip 2.9 ab 4.4 12.5 ab 18.1 ab 21.7 bc 46.7 cd

    Inoculated -- -- 3.8 ab 10.6 11.3 ab 29.4 b 38.2 c 52.5 d 1 Disease severity index (DSI) was determined using the following equation:

    DSI = [(class no.)(no. of carrots in each class)] x 100 (total no. of carrots per treatment)(no. classes - 1) 2 Based on a scale of 1 to 6, where 0 = no rot, 1 = 0-5%, 2 = 6-10%, 3 = 11-25%, 4 = 26-50%, 5 = 51-75%, 6 = 76-100%. 3 Numbers in a column followed by the same letter were not significantly different at P = 0.05, Tukeys test. 4 ns indicates no significant differences found among the treatments Funding for this project was provided by the Pest Management Centre, Agriculture and Agri-Food Canada, and the Sustainable Production Systems Program of the Ontario Ministry of Agriculture, Food and Rural Affairs & University of Guelph.

  • CROP: Carrot (Daucus carota), cvs. Cellobunch, Nevada, Envy, and Maverick PEST: Sclerotinia rot of carrot, (Sclerotinia sclerotiorum (Lib.) de Bary) AUTHORS: MCDONALD MR1, VANDER KOOI K1 & GOSSEN BD2 1University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station 2Agriculture and Agri-Food Canada, Saskatoon TITLE: COMPARISON OF VARIOUS CARROT CULTIVARS INOCULATED WITH

    SCLEROTINIA SCLEROTIORUM FOR RESISTANCE TO SCLEROTINIA ROT OF CARROT, 2008-2009

    MATERIALS: Cellobunch, Envy (Seminis Vegetable Seeds), Nevada (Bejo Seeds) and Maverick (Nunhems Seeds) METHODS: Carrots of various cultivars were direct seeded (82 seeds/m) into raised beds of organic soil (pH 6.3, organic matter 72.7%) on 22 May 2008 using a Stan Hay Precision seeder at the Muck Crops Research Station, Holland Marsh Ontario. A randomized complete block arrangement with four replicates per treatment was used. Each experimental unit consisted of four 5 m long rows, 42 cm apart. Inoculum was obtained from Dr. B. Gossen AAFC. On 31 July the plot was inoculated by evenly spreading paper strip inoculum, at the rate of 1.4 g/m, on the soil of the 2 inside rows of the 4-row experimental unit. At harvest on 17 October 2008, a 2.32 m section was pulled. The roots were placed in a plastic tote, one per experimental unit, and placed in Filacell storage at 1 C, 95% RH. On 18 March 2009, the storage sample was removed, assessed for disease, based on a scale of 1 to 10, where 0 = no rot, 1 = 1-10%, 2 = 11-20%, 3 = 21-30%, 4 = 31-40%, 5 = 41-50%, 6 = 51-60%, 7 = 61-70%, 8 = 71-80%, 9 = 81-90%, 10 = 91-100%. Healthy and diseased carrots weighed and weights recorded. The air temperatures in 2008 were below the long term (10 year) average for May (10.7C), August (17.9C) September (14.7C), and October (7.4C), average for July (20.4C) and above average for June (19.2C). The long term (10 year) average temperatures were: May 12.6C, June 18.4C, July 20.3C, August 19.2C, September 15.7C and October 9.0C. Monthly rainfall was below the long term (10 year) average for May (48 mm) and June (68 mm), above average for July (137 mm) and August (63 mm), and average for September (82 mm) and October (54 mm). The long term (10 year) rainfall averages were: May 80 mm, June 76 mm, July 69 mm, August 56 mm, September 80 mm and October 59 mm. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix V.9. Means separation was obtained using Fishers Protected LSD test at P = 0.05 level of significance. RESULTS: As presented in Table 1 CONCLUSIONS: The incidence of sclerotinia rot was very low in this trial. No significant differences were found among the cultivars in the percent disease found in the trial. Significant differences were found in marketable yield, however different carrot phenotype most likely influenced overall yield.

  • Table 1. Percentage Sclerotinia sclerotiorum infection of various carrot cultivars after inoculation in the field with S. sclerotiorum and five months in Filacell storage at Muck Crops Research Station, Holland Marsh, Ontario, 2008-09

    Cultivar % Carrots Infected with Sclerotinia t/ha

    Envy 0.3 ns1 95.9 a2 Cellobunch 0.0 95.0 a Maverick 2.4 83.5 b Nevada 3.4 82.2 b 1 ns indicated no significant differences were found among the treatments 2 Numbers in a column followed by the same letter were not significantly different at P = 0.05, Fishers Protected LSD test. Funding for this project was supplied by the OMAFRA/University of Guelph sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota), cv. Envy PEST: Sclerotinia rot of carrot, (Sclerotinia sclerotiorum (Lib.) de Bary) AUTHORS: MCDONALD MR1, VANDER KOOI K1 & GOSSEN BD2 1University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station 2Agriculture and Agri-Food, Saskatoon TITLE: EVALUATION OF FUNGICIDES ON CARROTS INOCULATED WITH

    SCLEROTINIA SCLEROTIORUM FOR SCLEROTINIA ROT OF CARROT DISEASE CONTROL, 2008-2009

    MATERIALS: PRISTINE (pyraclostrobin 25.2%, boscalid 12.8%), LANCE (boscalid 70%) METHODS: Carrots, cv. Envy (Stokes Seeds) were direct seeded (82 seeds/m) on raised beds, into organic soil (pH 6.3, organic matter 74.0%) on 22 May 2008 using a Stan Hay Precision seeder at the Muck Crops Research Station, Holland Marsh Ontario. A randomized complete block arrangement with four replicates per treatment was used. Each experimental unit consisted of four, 5 m long rows, 42 cm apart. Treatments were: PRISTINE at 737 g/ha on carrots inoculated and not inoculated with sclerotinia and LANCE at 630 g/ha on carrots inoculated and not inoculated with sclerotinia. An untreated, non-inoculated check and an untreated inoculated check were also included. Treatments were applied on 6, 20, 3 August, 19 September and 3 October using a pull-type plot sprayer with TeeJet D-3 hollow cone nozzles at 690 kPa (boom) in 500 L/ha of water. On 31 July treatments were inoculated by evenly spreading paper strip inoculum, 1.4 g/m, on the soil in the 2 intercrop rows per experimental unit. Inoculum was provided by Dr. B. Gossen, AAFC. At harvest on 4 November 2008, a 2.32 m sample was pulled, placed in a plastic tote and placed in Filacell storage at 1 C, 95% RH. On 23 July 2009, the bulk storage sample was removed, assessed for disease and healthy and diseased carrots weighed. Each bin was given a visual rating for rot based on a scale of 1 10, where 0 = no rot, 1 = 1-10%, 2 = 11-20%, 3 = 21-30%, 4 = 31-40%, 5 = 41-50%, 6 = 51-60%, 7 = 61-70%, 8 = 71-80%, 9 = 81-90%, and 10 = 91-100% rot. The air temperatures in 2008 were below the long term (10 year) average for May (10.7C), August (17.9C) September (14.7C), and October (7.4C), average for July (20.4C) and above average for June (19.2C). The long term (10 year) average temperatures were: May 12.6C, June 18.4C, July 20.3C, August 19.2C, September 15.7C and October 9.0C. Monthly rainfall was below the long term (10 year) average for May (48 mm) and June (68 mm), above average for July (137 mm) and August (63 mm), and average for September (82 mm) and October (54 mm). The long term (10 year) rainfall averages were: May 80 mm, June 76 mm, July 69 mm, August 56 mm, September 80 mm and October 59 mm. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix V.9. Means separation was obtained using Fishers Protected LSD test at P = 0.05 level of significance. RESULTS: As presented in Table 1 CONCLUSIONS: There was no significant difference among the treatments in percent disease, average degree of rot, or yield of either inoculated or non-inoculated carrots (Table 1). This may be due to the efficiency of the Filacell storage.

  • Table 1. Evaluation of LANCE and PRISTINE for control of sclerotinia rot in carrots inoculated with Sclerotinia sclerotiorum grown and stored in the Holland Marsh, Ontario, 2008-2009.

    Treatment Inoculation Rate (g/ha) % Diseased after storage

    Average Degree of Rot

    Rating1 Yield (t/ha)

    LANCE Inoculated 630 20.4 ns2 1.5 ns 79.8 ns

    LANCE Non-inoculated 630 18.9 1.3 85.5

    PRISTINE Inoculated 737 17.3 1.8 88.1

    PRISTINE Non-inoculated 737 15.5 1.5 86.7

    Check Inoculated -- 16.6 1.3 75.5

    Check Non-inoculated -- 15.9 2.3 82.0 1 Average of visual rating of rot overall in bin based on a scale of 1 10, where 0 = not rot, 1 = 1-10%, 2 = 11-20%, 3 = 21-30%, 4 = 31-40%, 5 = 41-50%, 6 = 51-60%, 7 = 61-70%, 8 = 71-80%, 9 = 81-90%, 10 = 91-100% 2 Not significantly different at P=0.05, Fishers Protected LSD test. Funding for this project was supplied by the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang.) cv. Envy PEST: Cavity spot (Pythium intermedium de Bary, Pythium irregulare Buisman, Pythium sulcatum Pratt & Mitchell, Pythium sylvaticum W.A. Campbell & J.W. Hendrix, Pythium ultimum Trow and Pythium violae Chesters & C.J. Hickman) AUTHORS: MCDONALD MR & VANDER KOOI K University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station TITLE: EVALUATION OF RANMAN FOR CONTROL OF CAVITY SPOT ON CARROTS,

    2009 MATERIALS: RANMAN 400SC (cyazofamid 34.5%), RIDOMIL (metalaxyl-M 1.0%), SYLGARD 309 (polysiloxane 80%) METHODS: The trial was conducted on organic soil (pH 6.4, organic matter 74.0%) naturally infested with Pythium spp. near the Muck Crops Research Station, Holland Marsh, Ontario. A randomized complete block design with four replicates per treatment was used. Carrots, cv. Envy, were direct seeded (82 seeds/m) on raised beds using a Stan Hay Precision seeder on 25 May. Each experimental unit consisted of two rows, 86 cm apart, 6 m in length. Treatments were: RANMAN at 440 mL/ha + SYLGARD at 150 mL/ha, 3 and 14 days after seeding (29 May and 8 June) and RIDOMIL at 735 g/ha applied 3 days after seeding (29 May) in a banded drench using a CO2 backpack sprayer equipped with a TeeJet 8002 nozzle followed by irrigation to move the product into the root zone. An untreated check was also included. On 10 September, a random sample of 25 carrots was removed from each treatment, and assessed for cavity spot. A 2.33 m sample was harvested on October 17, placed into cold storage and assessed for marketable yield and forking caused by Pythium on 21 December. A random sample of 50 carrots was removed and assessed for cavity spot. On both assessment dates carrots were washed in a small drum washer, examined for cavity spot lesions and sorted into classes based on the size of the largest lesion (measured as horizontal length). The six classes were as follows: no disease; very light < 1mm; light 1-2 mm; medium 3-5 mm; heavy 6-10 mm; very heavy > 10 mm. The disease severity index (DSI) was determined by the following equation:

    DSI = [(class no.)(no. of carrots in each class)] x 100 (total no. carrots per sample)(no. classes -1) The air temperatures in were below the long term (10 year) average for June (16.5C), July (17.9C) and October (7.3C) and average for May (12.6C), August (19.4C) and September (14.9C). The long term (10 year) average temperatures were: May 12.1C, June 18.2C, July 19.9C, August 19.3C, September 15.5C and October 8.9C. Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for May (117 mm), July (135 mm), August (89 mm) and October (62 mm). The long term (10 year) rainfall averages were: May 86 mm, June 74 mm, July 76 mm, August 57 mm, September 72 mm and October 59 mm. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix V.9. Means separation was obtained using Fishers Protected LSD test at P = 0.05 level of significance. The data were grouped in two different ways for analysis, because some of the SYLGARD alone treatments introduced a higher level of variability to the analysis. The first was to compare the two RANMAN treatments only with the untreated check (Table 1). The second analysis (Table 2) evaluated all treatments. RESULTS: As presented in Tables 1 & 2 CONCLUSIONS: Cavity spot pressure was relatively high in this trial, probably as a result of the higher than average rainfall in July and August. Significant differences were observed in percent disease at both assessment dates and the DSI at the 8 January assessment date when the RANMAN treatments are compared to the untreated check (Table 1). Significant differences were found in marketable yield at harvest (Table 2). All fungicide treatments had significantly higher yields than the check. No pythotoxicity was observed in any of the treatments.

  • Table 1. Disease incidence and severity (DSI) of cavity spot for carrots treated with various fungicides, grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009.

    Treatment Rate

    (mL/ha)

    Application Timing (DAS)

    Disease Incidence (%) DSI2

    10 Sep 21 Dec 10 Sep 21 Dec

    RANMAN + SYLGARD 440 + 150 14 86.7 ns1 96.0 ns 30.9 ns 54.9 ns

    RANMAN + SYLGARD 440 + 150 3 89.0 93.6 32.8 53.0

    RIDOMIL 735 (g/ha) 3 83.7 93.6 32.8 53.3

    Check -- -- 95.1 96.0 40.6 55.0 1 ns indicates no significant difference, P = 0.05 2 Disease severity index (DSI) was determined using the following equation:

    DSI = [(class no.)(no. of carrots in each class)] x 100 (total no. carrots per sample)(no. classes -1) Table 2. Percent marketable and marketable yield for carrots treated with various fungicides, grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009.

    Treatment Rate

    (mL/ha)

    Application Timing (DAS)

    % Marketable Marketable Yield

    t/ha

    RANMAN + SYLGARD 440 + 150 14 93.6 ns1 84.3 a2

    RANMAN + SYLGARD 440 + 150 3 92.6 81.8 a

    RIDOMIL 735 (g/ha) 3 90.1 76.4 a

    Check -- -- 79.6 64.8 b 1 ns indicates no significant difference, P = 0.05 2 Numbers in a column followed by the same letter are not significantly different at P = 0.05, Fishers Protected LSD test Funding for this project was supplied by FMC Corp. and the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang.) cv. Envy PEST: Cavity spot (Pythium intermedium de Bary, Pythium irregulare Buisman, Pythium sulcatum Pratt & Mitchell, Pythium sylvaticum W.A. Campbell & J.W. Hendrix, Pythium ultimum Trow and Pythium violae Chesters & C.J. Hickman) AUTHORS: MCDONALD MR & VANDER KOOI K University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station TITLE: EVALUATION OF POLYVERSUM (PYTHIUM OLIGANDRUM) FOR

    MANAGEMENT OF CAVITY SPOT ON CARROTS, 2009 MATERIALS: POLYVERSUM (Pythium oligandrum 1 x 105 cfu/g), RANMAN 400SC (cyazofamid 34.5%) METHODS: The trial was conducted on organic soil (pH 5.8, organic matter 76.4%) naturally infested with Pythium spp. at the Muck Crops Research Station, Holland Marsh, Ontario. Carrots, cv. Envy, were direct seeded (82 seeds/m) on raised beds using a Stan Hay Precision seeder on 25 June. A randomized complete block design with four replicates per treatment was used. Each replicate consisted of two rows, 86 cm apart, 6 m in length. Treatments were: POLYVERSUM at 100 and 200 g/ha and RANMAN at 440 mL + SYLGARD at 0.15 L/ha. An untreated check was also included. Treatments were applied on 30 June using a CO2 backpack spray equipped with a single 1004 TeeJet nozzle calibrated to apply 1000 L /ha at 240 kPa. A 2.32 m section of row was harvested on 20 October, placed into cold storage and assessed for cavity spot on 13 January, 2010. Carrots were washed in a small drum washer and examined for forking damage. Healthy and forked carrots were counted and weighed. A 50-carrot sample was randomly chosen from the healthy (non-forked) carrots and visually examined for cavity spot lesions and sorted into classes based on the size of the largest lesion (measured as horizontal length). The six classes were as follows: no disease, very light (< 1mm), light (1-2 mm), medium (3-5 mm), heavy (6-10 mm), and very heavy (> 10 mm). Carrots were grouped by colour and by cultivar when assessed for disease incidence and severity. The disease severity index (DSI) was determined by the following equation:

    DSI = [(class no.)(no. of carrots in each class) x 100 (total no. of carrots per sample)(no. classes 1) The air temperatures in 2009 were below the long term (10 year) average for June (16.5C), July (17.9C) and October (7.3C), and average for August (19.4C) and September (14.9C). The long term (10 year) average temperatures were: June 18.2C, July 19.9C, August 19.3C, September 15.5C and October 8.9C. Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for July (135 mm), August (89 mm) and October (62 mm). The long term (10 year) rainfall averages were: June 74 mm, July 76 mm, August 57 mm, September 72 mm and October 59 mm. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix V.9. Means separation was obtained using Fishers Protected LSD test at P = 0.05 level of significance. RESULTS: As presented in Table 1 CONCLUSIONS: Cavity spot severity was moderate in this trial and disease severity was low. No significant differences in the incidence or severity of clubroot were found among the treatments. No significant differences in yield were found among the treatments (Table 1). Numerically, the untreated check had the highest incidence of cavity spot and lowest yield.

  • Table 1. Incidence and severity (DSI) of cavity spot in carrots, cv. Envy, grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009.

    Treatment Rate per ha Disease

    Incidence (%)

    DSI1 % Forked %

    Marketable Yield (t/ha)

    RANMAN + SYLGARD 440 mL + 0.15 L 42.5 ns

    2 18.0 ns 16.7 ns 83.3 ns 39.3 ns

    POLYVERSUM 200 g 47.5 19.8 16.4 83.6 37.1

    POLYVERSUM 100 g 45.0 19.5 13.2 86.8 39.0

    Check -- 52.5 21.6 20.1 79.9 37.0 1 Disease severity index (DSI) was determined using the following equation:

    DSI = [(class no.)(no. of carrots in each class)]

    x 100 (total no. carrots per sample)(no. classes -1) 2 ns indicates no significant differences were found among the treatments at P = 0.05, Fishers Protected LSD Test Funding for this project was supplied by Beta Biologics and by the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang.) PESTS: Cavity spot (Pythium intermedium de Bary, Pythium irregulare Buisman, Pythium sulcatum Pratt & Mitchell, Pythium sylvaticum W.A. Campbell & J.W. Hendrix, Pythium ultimum Trow and Pythium violae Chesters & C.J. Hickman) AUTHORS: MCDONALD MR & VANDER KOOI K University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station TITLE: EVALUATION OF VARIOUS COLOURED CARROTS FOR SUSCEPTIBILITY

    TO CAVITY SPOT, 2009 MATERIALS: Carrot breeding lines from the University of Wisconsin, Mello Yello, White Satin, Purple Haze and Nevada from Bejo Seeds Inc., Envy and Cellobunch from Seminis Vegetable Seeds, and Atomic Red from Johnnys Select Seeds. METHODS: The trial was conducted on organic soil (pH 6.3, organic matter 74.0%) naturally infested with Pythium spp. near the Muck Crops Research Station, Holland Marsh, Ontario. A randomized complete block design with four replicates per treatment was used. Carrots were direct seeded (70-80 seeds/m) on raised beds using a push V-belt seeder on 1 June. Each replicate consisted of two rows, 86 cm apart, 6 m in length. On 10 September, a random sample of 25 carrots was removed from each treatment and assessed for cavity spot. A 50-carrot sample was harvested on 23 October, placed into cold storage and assessed for cavity spot on 22, 23, 24 December and 4 January. Carrots were washed in a small drum washer, visually examined for cavity spot lesions and sorted into classes based on the size of the largest lesion (measured as horizontal length). The six classes were as follows: no disease; very light (< 1mm), light (1-2 mm), medium (3-5 mm), heavy (6-10 mm), very heavy (> 10 mm). Carrots were grouped by colour and by cultivar when assessed for disease incidence and severity. The disease severity index (DSI) was determined by the following equation:

    DSI = [(class no.)(no. of carrots in each class)] x 100 (total no. carrots per sample)(no. classes -1)

    The air temperatures in 2009 were below the long term (10 year) average for June (16.5C), July (17.9C) and October (7.3C), and average for August (19.4C) and September (14.9C). The long term (10 year) average temperatures were: June 18.2C, July 19.9C, August 19.3C, September 15.5C and October 8.9C. Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for July (135 mm), August (89 mm) and October (62 mm). The long term (10 year) rainfall averages were: June 74 mm, July 76 mm, August 57 mm, September 72 mm and October 59 mm.. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix 9. Means separation was obtained using Fishers Protected LSD test at P = 0.05 level of significance. RESULTS: As presented in Tables 1, 2 and 3 CONCLUSIONS: The incidence of cavity spot was very high in 2009 with six cultivars recording >75% incidence at the December assessment. Significant differences in incidence and severity of cavity spot were found among the cultivars at both assessment dates (Table 1). At the September assessment date Purple Haze had a significantly lower incidence of cavity spot than all other cultivars and had lower disease severity than all other cultivars except Envy. Envy and breeding line dark orange had significantly less incidence of cavity spot than Mello Yello and Atomic Red. Envy, Cellobunch and White Satin had significantly lower disease severity than Mello Yello and Atomic Red. At the December assessment date Purple Haze had significantly lower cavity spot incidence and severity than all other cultivars and breeding lines. Breeding lines purple, yellow and red and commercial variety Cellobunch had significantly lower cavity spot incidence and severity than Mello Yello, White Satin,

  • Atomic Red and breeding line dark orange. The plant stand was low for breeding lines purple, yellow, red and white and therefore were not pulled for assessment in September. When carrots were grouped by colour, significant differences were found in incidence and severity of cavity spot (Table 2). Purple carrots had significantly less incidence and severity of cavity spot than all other colour groups. Yellow, orange and red carrots had significantly lower disease severity than white carrots. Plant stands were low for breeding lines, consequently colour classes were not well represented and therefore could not be grouped for analysis at the September assessment. Table 1. Disease incidence and disease severity index (DSI) of cavity spot in coloured carrots grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009.

    Cultivar Source1 Colour Disease Incidence (%) DSI2

    10 September 22 December 10 September 22 December Purple Haze Bejo purple 36.0 a3 8.5 a 9.1 a 4.5 a Purple UW purple -- 45.0 b -- 26.1 b Yellow UW yellow -- 54.7 bc -- 34.0 bcd Cellobunch Sem orange 80.0 bc 71.6 cd 25.1 bc 31.4 bc Red UW red -- 74.6 de -- 50.2 c White UW white -- 75.7 def -- 42.9 cde Envy Sem orange 75.7 b 89.2 def 21.3 ab 43.0 cde Mello Yello Bejo yellow 94.7 c 91.8 ef 46.9 de 47.4 de Dark Orange UW orange 76.0 b 93.5 ef 34.7 cd 55.2 e White Satin Bejo white 86.7 bc 93.5 ef 31.2 bc 50.3 e Atomic Red JSS red 93.1 c 94.0 f 51.7 e 71.4 f 1 UW = University of Wisconsin, Sem = Seminis Vegetable Seed, Bejo = Bejo Seeds Inc., JSS = Johnnys Selected Seeds 2 Disease severity index (DSI) was determined using the following equation:

    DSI = [(class no.)(no. of carrots in each class)]

    x 100 (total no. carrots per sample)(no. classes -1) 3 Numbers in a column followed by the same letter were not significantly different at P=0.05, Fishers Protected LSD Test. Table 2. Disease incidence and severity (DSI) of cavity spot assessed in December, of various coloured carrots grouped by colour, grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009. Colour Disease Incidence (%) DSI1 Purple 22.5 a2 12.8 a Yellow 73.3 b 40.7 b Orange 81.7 b 41.8 b Red 84.3 b 47.4 b White 87.5 b 60.8 c 1 Disease severity index (DSI) was determined using the following equation:

    DSI = [(class no.)(no. of carrots in each class)]

    x 100 (total no. carrots per sample)(no. classes -1) 2 Numbers in a column followed by the same letter were not significantly different at P=0.05, Fishers Protected LSD Test. Funding for this project was supplied by the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang.) PEST: Cavity spot (Pythium intermedium de Bary, Pythium irregulare Buisman, Pythium sulcatum Pratt & Mitchell, Pythium sylvaticum W.A. Campbell & J.W. Hendrix, Pythium ultimum Trow and Pythium violae Chesters & C.J. Hickman) AUTHORS: MCDONALD MR & VANDER KOOI K University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station TITLE: EVALUATION OF VARIOUS CARROTS CULTIVARS FOR SUSCEPTIBILITY

    TO CAVITY SPOT, 2009 MATERIALS: Eight commercial carrot cultivars: Envy and Cellobunch from Seminis Vegetable Seeds, Purple Haze and Nevada from Bejo Seeds Inc., Six Pak II from Harris Moran Seed Co., Apache, and Choctaw from Nunhems Vegetable Seeds, Chantenay Red Cored from Vesey Seeds and a red carrot from the University of Wisconsin breeding line. METHODS: The trial was conducted on organic soil (pH 6.3, organic matter 74.0%) naturally infested with Pythium spp. at the Muck Crops Research Station, Holland Marsh, Ontario. A randomized complete block design with four replicates per treatment was used. Carrots were direct seeded (70-80 seeds/m) on raised beds using a push V-belt seeder on 1 June. Each replicate consisted of two rows, 86 cm apart, 6 m in length. On 10 September, a random sample of 25 carrots was removed from each treatment and assessed for cavity spot. A 50-carrot sample was harvested on 23 October, placed into cold storage and assessed for cavity spot on 22, 23, 24 December and 4 January. Carrots were washed in a small drum washer, visually examined for cavity spot lesions and sorted into classes based on the size of the largest lesion (measured as horizontal length). The six classes were as follows: no disease, very light (< 1mm), light (1-2 mm), medium (3-5 mm), heavy (6-10 mm), and very heavy (> 10 mm). Carrots were grouped by colour and by cultivar when assessed for disease incidence and severity. The disease severity index (DSI) was determined by the following equation:

    DSI = [(class no.)(no. of carrots in each class)] x 100 (total no. carrots per sample)(no. classes -1)

    The air temperatures in 2009 were below the long term (10 year) average for June (16.5 C), July (17.9 C) and October (7.3 C), and average for August (19.4 C) and September (14.9 C). The long term (10 year) average temperatures were: June 18.2 C, July 19.9 C, August 19.3 C, September 15.5 C and October 8.9 C. Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for July (135 mm), August (89 mm) and October (62 mm). The long term (10 year) rainfall averages were: June 74 mm, July 76 mm, August 57 mm, September 72 mm and October 59 mm. Data were analyzed using the General Analysis of Variance function of the Linear Models section of Statistix 9. Means separation was obtained using Fishers Protected LSD Test at P = 0.05 level of significance. RESULTS: As presented in Table 1 CONCLUSIONS: Cavity spot incidence was high in 2009. Significant differences were found among cultivars for disease incidence and disease severity index on both assessment dates (Table 1). At the 10 September assessment date Purple Haze had a significantly lower incidence of cavity spot than all other carrots except commercial variety Nevada and a significantly lower severity of cavity spot than Cellobunch, Envy, Apache, Red Cored Chantenay and Choctaw. At the 22 December assessment date cultivar Purple Haze had significantly lower incidence and severity of cavity spot than all other carrots. Commercial variety Six Pak II had significantly lower incidence of cavity spot than Nevada, Choctaw, Chantenay Red Cored, Envy and Apache. Six Pak II had significantly

  • lower severity of cavity spot than Envy, Choctaw, Apache, Chantenay Red Cored and the UW breeding line red. Table 1. Disease incidence and disease severity index (DSI) of cavity spot in carrot cultivar grown at the Muck Crops Research Station, Holland Marsh, Ontario, 2009.

    Cultivar Colour Disease Incidence (%) DSI1

    10 September 22 December 10 September 22 December

    Purple Haze purple 36.0 a2 8.5 a 9.1 a 4.5 a Six Pak II orange 61.3 b 62.8 b 18.7 abc 26.5 b Cellobunch orange 80.0 b 71.6 bc 25.1 bcd 31.4 bc Red3 red -- 74.6 bcd -- 50.2 e Nevada orange 56.9 ab 79.6 cde 16.5 ab 35.7 bcd Choctaw orange 78.7 b 81.0 cde 32.5 d 43.9 de Red Cored Chantenay orange 69.5 b 85.8 de 28.7 cd 49.5 e Envy orange 75.7 b 89.2 e 21.3 bcd 43.0 cde Apache orange 66.2 b 89.8 e 29.2 cd 48.9 e 1 Disease severity index (DSI) was determined using the following equation:

    DSI = [(class no.)(no. of carrots in each class)]

    x 100 (total no. carrots per sample)(no. classes -1) 2 Numbers in a column followed by the same letter were not significantly different at P=0.05, Fishers Protected LSD Test. 3 University of Wisconsin breeding line red carrot Funding for this project was supplied by the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang) PEST: Sclerotinia rot of carrot (Sclerotinia sclerotiorum (Lib.) de Bary) AUTHORS: PARKER M1, MCDONALD MR1 & BOLAND GJ2 1University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station 2University of Guelph, School of Environmental Sciences TITLE: DETECTION OF ASCOSPORES OF SCLEROTINIA SCLEROTIORUM

    CORRELATES AMONG SITES WITHIN A REGION AND TO DISEASE INCIDENCE

    MATERIALS: Blue Plate Test and Andersen N6 Impactor, both using Sclerotinia semi-selective

    medium METHODS: This study is to improve methods to forecast disease risk by comparing selected spore-trapping methods to detect ascospores of the pathogen and comparing concentrations of ascospores in 2008 and 2009 at multiple sites within a region having a history of carrot production and sclerotinia rot of carrot. Ascospore trapping methods being evaluated are based on passive and active deposition of ascospores onto Sclerotinia selective medium using the Blue Plate Test and the Andersen N6 Impactor, respectively. Spore traps were located in the Bradford Marsh, Ontario at one and two sites of the Muck Crops Research Station in 2008 and 2009, respectively, and at two commercial fields in both years. Ascospore sampling began 29 and 8 July, continuing until 8 and 15 Oct in 2008 and 2009, respectively, and was conducted 2-3 times weekly. The Blue Plate Test consisted of exposing Petri dishes containing Sclerotinia selective medium placed on a covered stand 1 m above the soil at approximately 45 degrees facing the prevailing wind for 3 hr during the period 10 h to 14 h. The Blue Plate Test was conducted at 6 locations at each site. The N6 Impactor was placed 1 m above the soil and Petri dishes containing Sclerotinia selective medium placed inside the sampler were exposed for three 10 min intervals at one sampling location per site. The Petri dishes were incubated at room temperature for 72 h, at which time putative colonies of S. sclerotiorum were counted and marked. Colonies were confirmed as S. sclerotiorum after 7-10 days incubation by the presence of sclerotia. In 2008, the air temperatures were below the long term (10 year) average for May (10.7C), August (17.9C) and September (14.7C), average for July (20.4C) and above average for June (19.2C). Monthly rainfall was below the long term (10 year) average for May (48 mm) and June (68 mm), above average for July (137 mm) and August (63 mm), and average for September (82 mm). In 2009, the air temperatures were below the long term (10 year) average for June (16.5C), July (17.9C) and October (7.3C), and average for May (12.6C), August (19.4C) and September (14.9C). Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for May (117 mm), July (135 mm), August (89 mm) and October (62 mm). All statistical analysis was performed using the proc corr procedure of SAS version 9.1 (SAS Institute, Cary, NC) with P = 0.05 level of significance.

  • RESULTS: In 2008, ascospores were detected using the Blue Plate Test from 29 July to 8 October with average counts from six dishes per site ranging from 0 to 28.5 ascospores. Ascospores were consistently detected or not detected between the three sites on 13 of 20 total sampling dates. Detected ascospores among the three sites using the Blue Plate Test and N6 Impactor did not significantly correlate. In 2009, ascospores were detected from 15 July to 15 September with average counts from six dishes per site ranging from 0 to 45 ascospores. Ascospores were consistently detected or not detected between the four sites on 15 of 22 total sampling dates. Detected ascospores between the three sites using the Blue Plate Test and N6 Impactor significantly correlated in 9 of 21 possible site combinations (r = 0.56 0.86, P < 0.0001 0.0223). In both years, the N6 Impactor consistently detected fewer ascospores compared to the Blue Plate Test. Disease incidence one week after ascospore detection significantly correlated at all three sites and two of four sites in 2008 and 2009, respectively (2008: r = 0.78 0.87, P = 0.0026 0.0118; 2009: r = 0.74 and 0.88, P = 0.0097 and 0.0095, respectively). CONCLUSIONS: Although ascospore counts did not significantly correlate among sites in 2008 using the Blue Plate Test or Andersen N6 Impactor, correlations in 2009 did significantly correlate among sites using both trapping methods. Despite insignificant correlations between ascospore counts and disease incidence at two sites in 2009, both were consistently low throughout the growing season. The results provide strong evidence that disease prediction is accurate, particularly when the number of detected ascospores is low, and that regional level forecasting is a viable tool to manage sclerotinia rot of carrot. Funding for this project was provided by the National Research Council of Canada (NSERC) and the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota subsp. sativus (Hoffm.) Arcang) PEST: Sclerotinia rot of carrot (Sclerotinia sclerotiorum (Lib.) de Bary) AUTHORS: PARKER M1, MCDONALD MR1 & BOLAND GJ2 1University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station 2University of Guelph, School of Environmental Sciences TITLE: DETECTION OF ASCOSPORES OF SCLEROTINIA SCLEROTIORUM

    PROVIDES ACCUTRATE TIMING FOR MANAGING SCLEROTINIA ROT OF CARROT

    MATERIALS: LANCE (boscalid 70%), ELEXA-4 (chitosan 4%) METHODS: The field trial was conducted at the Muck Crops Research Station in the Bradford Marsh in 2009 in organic soil naturally infested with sclerotinia rot of carrot. A split plot design with treatment as the main plot arranged as a randomised complete block with cultivar allocated to each replicate as the sub-plot was used. Each replicate consisted of 4 rows, 2 rows side-by-side of each cultivar, 5 m in length and 86 cm apart centre-to-centre having a 40 cm wide growing area. Carrot cultivars Envy and Nevada were seeded at a rate of 80 seeds m-1. LANCE was applied when within field detected ascospores of S. sclerotiorum surpassed the sclerotinia forecast model threshold of 5 detected ascospores using the Blue Plate Test on sclerotinia semi-selective medium. ELEXA-4 was applied bi-weekly, beginning at carrot canopy closure on 31 July. Each chemical treatment was also combined with trimming the carrot canopy, which occurred on 12 August when ascospore counts surpassed the forecast threshold after canopy closure. The incidence of sclerotinia rot on carrot foliage was evaluated as the percentage of plants in the assessment area that had at least one lesion per leaf or petiole. The air temperatures were below the long term (10 year) average for June (16.5C), July (17.9C) and October (7.3C), and average for May (12.6C), August (19.4C) and September (14.9C). Monthly rainfall was below the long term (10 year) average for June (49 mm) and September (51 mm) and above average for May (117 mm), July (135 mm), August (89 mm) and October (62 mm). Data were analysed using the proc glm procedure of SAS version 9.1. Means separation was obtained using the Tukeys test with P = 0.05 level of significance. RESULTS: As presented in Table 1. CONCLUSIONS: LANCE and ELEXA-4 were equally effective in reducing disease incidence when applied as a standalone treatment. Canopy trimming combined with ELEXA-4 or LANCE treatment significantly reduced disease incidence compared to either treatment alone. Disease developed in trimming treatments after the canopy closed and environmental conditions were conducive to disease development. The results demonstrate that managing sclerotinia rot of carrot is effective when accurately-timed according to the number of detected ascospores within the crop.

  • Table 1. Field evaluation of BOSCALID, ELEXA-4 and canopy trimming for management of sclerotinia rot of carrot, Holland Marsh, Ontario, 2009.

    Treatment

    Number of Applications

    AUDPC 1

    LANCE @ 441 g/ha and trimming

    3

    22 a 2

    ELEXA-4 @ 0.2% chitosan and trimming 5

    70 a

    LANCE @ 441 g/ha 3

    215 b

    ELEXA-4 @ 0.2% chitosan 5

    252 b

    Check 0

    564 c

    se

    27

    1 Area under the disease progress curve. 2 Numbers in a column followed by the same letter are not significantly different at P = 0.05, Tukeys

    Test.

    Funding for this project was provided by the National Research Council of Canada (NSERC) and the OMAFRA/University of Guelph Sustainable Production Systems Program.

  • CROP: Carrot (Daucus carota L. var. Envy) PEST: Sclerotinia rot (Sclerotinia sclerotiorum (Lib.) De Bary) AUTHORS: COWAN JE & BOLAND GJ University of Guelph, School of Environmental Sciences TITLE: INFLUENCE OF FREEZING TEMPERATURES AND THE CONTANS WG

    BIOLOGICAL CONTROL PRODUCT ON GERMINATION OF SCLEROTIA OF SCLEROTINIA SCLEROTIORUM IN CARROT

    MATERIALS: CONTANS WG (Coniothyrium minitans Campbell) METHODS: In May, 2008, twelve replications (25 sclerotia each) of two batches of Sclerotinia sclerotiorum isolate Ss274, produced three months apart on potato dextrose agar and fully conditioned at 4C for apothecia production (carpogenic germination), were exposed for 28 days to one of three temperature treatments in controlled environments (constant -13C, 10C, and 14 two-day -1310C freeze-thaw (FT) cycles), subsequently immersed for one day in either sterile water or a 1x102 conidia/ml suspension of CONTANS WG (Coniothyrium minitans), and then placed into one of two organic soil field plots at the Muck Crops Research Station (MCRS), Kettleby, Ontario. Daucus carota, var. Envy, was seeded at a rate of 85 seeds/m with a row spacing of 86 cm in both 14 x 14 m plots. Plots were set up as randomized complete block designs with six replications per plot (rows) and at least 1 m of row as a buffer surrounding each plot and between each replication. On 12 June (plot 1) and 17 June (plot 2), sclerotia were placed in grids set up in the middle of each row by treatment and covered with 0.5 cm of field soil. Production of apothecia from S. sclerotiorum sclerotia was monitored weekly until 16 October, 2008 as total percent cumulative carpogenic germination. The experiment was repeated in 2009 using two S. sclerotiorum isolates (Ss274 and ZQ 35-10) produced at the same time, with sclerotia placed into the field on 12 June (plot 1) and 15 June (plot 2). Apothecia production was monitored weekly until 14 October, 2009. In total, six experiments (i.e., repetitions defined by field plot, sclerotia production time, and year) were completed over two years for isolate Ss274, and two experiments (i.e., field plot repetitions) were completed for isolate ZQ 35-10. Total percent cumulative carpogenic germination data from the final day of observations were analyzed separately by plot and year as randomized complete block designs within the General Linear Model (GLM) procedure of the Statistical Analysis Software (SAS) program (Windows version 9.1.3., SAS Institute Inc., Cary, NC, USA). All data were normal and subjected to analyses of variances (ANOVAs) with six replications to detect main treatment effects and/or possible interactions among relevant variables of isolate/batch, temperature, and biological control. Sets of 25 sclerotia were considered experimental units for the analyses. Means comparisons were also conducted on the data using Bonferroni (Dunn) t tests (=0.05). RESULTS: As presented in Table 1 CONCLUSIONS: Freezing and FT treatments alone (without the addition of CONTANS WG) did not reduce carpogenic germination of either S. sclerotiorum isolate relative to the 10C control (except one of six repetitions where the FT treatment was slightly reduced). However, for isolate Ss274, four of six repetitions exhibited a temperature biological control interaction where the -13C treatment was reduced the most by CONTANS WG (at the 1x102 conidia/ml experimental rate, which was much less than the recommended rate of 2-4 kg/ha for 0-10 cm incorporation into soil) compared to the other two temperature treatments (Table 1). The one 2008 repetition that lacked the interaction had all temperatures reduced by CONTANS WG, while the one 2009 repetition lacking the interaction showed no CONTANS WG effects following any temperature treatment. CONTANS WG reduced germination of

  • Ss274 sclerotia exposed to the FT treatment in only two of six repetitions; however, in all repetitions, the FT treatment was never different than the freezing treatment when both had CONTANS WG applied. The apparent discrepancy is because without CONTANS WG, the FT treatment was always slightly lower (but not statistically significant) than all other temperature treatments. Isolate ZQ 35-10 tested in 2009 yielded no temperature or biological control effects, suggesting that either the environmental conditions rendered the CONTANS WG ineffective, and/or that different isolates of S. sclerotiorum differ in their response to freezing temperatures and CONTANS WG. Thus, freezing temperatures of at least -13C for 28 days are capable of making at least one S. sclerotiorum isolate more susceptible to CONTANS WG (C. minitans). However, not all isolates become more susceptible following freezing exposure, so freezing temperatures in southern Ontario may not always improve the efficacy of CONTANS WG, but the potential is there. Table 1. Representative table of cumulative percent carpogenic germination from carrot plot 1 by 16 October, 2008, showing typical trends. Means are presented from highest to lowest and are averages across six replications. Different letters denote significant differences between means (=0.05).

    Temperature Treatment CONTANS WG Treatment Carpogenic Germination Means

    -13C 0 conidia/ml 72.7 a 10C 0 conidia/ml 66.3 a freeze-thaw cycles 0 conidia/ml 57.3 a 10C 1x102 conidia/ml 45.3 ab freeze-thaw cycles 1x102 conidia/ml 18.7 bc -13C 1x102 conidia/ml 2.7 c This project was funded by the National Science and Engineering Research Council (NSERC) and the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). Research and technical support was provided by Dr. Mary Ruth McDonald and research personnel at the Muck Crops Research Station, Kettleby, Ontario.

  • CROP: Carrot (Daucus carota.), cv. Envy Celery (Apium graveolens) cv. Sabroso AUTHORS: SWANTON C J, JANSE S & CHANDLER K University of Guelph, Dept. of Plant Agriculture, Muck Crops Research Station TITLE: HERBICIDE TOLERANCE IN CARROTS AND CELERY, 2009 MATERIALS: GESAGARD (prometryne 48%), DUAL II MAGNUM (s-metolachlor/benoxacor 91.5%), PROWL H2O (pendimethalin 45.5%), NORTRON (ethofumesate 48%). OBJECTIVE: To evaluate GESAGARD, DUAL II MAGNUM, PROWL H2O, and NORTRON for crop tolerance and efficacy in carrots and celery on muck soils. METHODS: The trial was conducted at a site with organic soil (organic matter 75%, pH 6.5) on the Muck Crops Research Station, Holland Marsh. Plots consisted of 2 hills, 86 cm apart and 4m long arranged