VG01096 White Rot – Spring Onions

The disease onion white rot – Sclerotium cepivorum – is a serious problem in bunching Allium crops, which include spring onions and shallots, sometimes causing crop losses of up to 50% in eastern Australia.

Before this project began vegetable growers used the fungicide procymidone to manage white rot, but complained that they were not getting good control.

The purpose of this project was to evaluate chemical and biological treatments for the control of the disease onion white rot on bunching onion crops.

This project has provided vegetable growers with more control options and an integrated strategy for the sustainable control of this soil-borne disease and to better inform them of the most appropriate and effective use of chemical and biological treatments for disease management on their farms.


Authors

Oscar Villalta Ian Porter
Denise Wite Alison Stewart
Kirsten McLean  

Stop the Rot � Managing Onion White Rot in
Spring Onions - 2005
Download 89kb

Recommendations :

This project has successfully developed new treatments which can be used alone or as part of an integrated package by vegetable growers to control onion white rot of bunching onions in their farms.

The project also provided valuable information that will assist vegetable growers to make informed decisions about the use of the biological control Trichoderma for managing onion white rot and soil health.

More successful control of white rot will be obtained when using an integrated management strategy that incorporates different treatments, strategies and tactics for disease control.

In general, there are three key strategies that growers can use to obtain effective and sustainable control of white rot on bunching onion crops.

  1. minimise the introduction and spread of the white rot pathogen within and between fields
  2. use of chemical and biological treatments that protect the roots of growing plants against infection
  3. reduce the population of sclerotia of S. cepivorum in soil

The project developed valuable information that will assist vegetable growers to make informed decisions about the appropriate use of the biological treatment Trichoderma for managing white rot and soil health in vegetable farms.

In sandy soils, the use (in-furrow) of pellets containing humic acids (eg Agrolig™, AgChem) will be required to help Trichoderma to grow better in these soils with low levels of organic matter.

Trichoderma growth is inhibited by nitrogen released from fertilizers and fresh composted chicken manure.

Therefore, these materials should not be applied for at least 2-3 weeks before and after sowing to allow Trichoderma spores/propagules to germinate and establish in soils.

Field rates of Filan™ and low-nitrogen soil amendments can be applied to soil treated with Trichoderma.

Trichoderma can be applied to soils treated with DADS several weeks after it was injected into soil.

In summary, in the short and medium-term, onion white rot can be managed with new fungicide treatments and biological controls, when possible.

For the long-term, the challenge remains to secure supply and registration of synthetic DADS for Allium industries in Australia.

The future of onion white rot research in Australia will be directed towards the development of cost-effective soil treatments to eradicate sclerotia of S. cepivorum and other important sclerotial pathogens of onions and vegetable crops from soils and development of integrated approaches for sustainable disease control.

Acknowledgments :

There were many people and organisations that provided assistance to make this research possible. They include:

  • DPI-Vic personal Craig Murdoch and Slobovan Vujivic for assistance with technology transfer activities, Peta Easton for technical assistance and Dr. Liz Minchinton for collection of survey data in NSW and SA.
  • John Hunt of Agrimm Technologies Ltd for his valuable advice on biocontrol trial preparation and Rob Stanic for arranging supply of Trichopel Ali52 and other products for field trials.

    The disease onion white rot – Sclerotium cepivorum – is a serious problem in bunching Allium crops, which include spring onions and shallots, sometimes causing crop losses of up to 50% in eastern Australia.

    Before this project began vegetable growers used the fungicide procymidone to manage white rot, but complained that they were not getting good control.

    The purpose of this project was to evaluate chemical and biological treatments for the control of the disease onion white rot on bunching onion crops.

    This project has provided vegetable growers with more control options and an integrated strategy for the sustainable control of this soil-borne disease and to better inform them of the most appropriate and effective use of chemical and biological treatments for disease management on their farms.


    Authors

    Oscar Villalta Ian Porter
    Denise Wite Alison Stewart
    Kirsten McLean  

    Stop the Rot – Managing Onion White Rot in
Spring Onions - 2005
    Download 89kb

    Recommendations :

    This project has successfully developed new treatments which can be used alone or as part of an integrated package by vegetable growers to control onion white rot of bunching onions in their farms.

    The project also provided valuable information that will assist vegetable growers to make informed decisions about the use of the biological control Trichoderma for managing onion white rot and soil health.

    More successful control of white rot will be obtained when using an integrated management strategy that incorporates different treatments, strategies and tactics for disease control.

    In general, there are three key strategies that growers can use to obtain effective and sustainable control of white rot on bunching onion crops.

    1. minimise the introduction and spread of the white rot pathogen within and between fields
    2. use of chemical and biological treatments that protect the roots of growing plants against infection
    3. reduce the population of sclerotia of S. cepivorum in soil

    The project developed valuable information that will assist vegetable growers to make informed decisions about the appropriate use of the biological treatment Trichoderma for managing white rot and soil health in vegetable farms.

    In sandy soils, the use (in-furrow) of pellets containing humic acids (eg Agrolig™, AgChem) will be required to help Trichoderma to grow better in these soils with low levels of organic matter.

    Trichoderma growth is inhibited by nitrogen released from fertilizers and fresh composted chicken manure.

    Therefore, these materials should not be applied for at least 2-3 weeks before and after sowing to allow Trichoderma spores/propagules to germinate and establish in soils.

    Field rates of Filan™ and low-nitrogen soil amendments can be applied to soil treated with Trichoderma.

    Trichoderma can be applied to soils treated with DADS several weeks after it was injected into soil.

    In summary, in the short and medium-term, onion white rot can be managed with new fungicide treatments and biological controls, when possible.

    For the long-term, the challenge remains to secure supply and registration of synthetic DADS for Allium industries in Australia.

    The future of onion white rot research in Australia will be directed towards the development of cost-effective soil treatments to eradicate sclerotia of S. cepivorum and other important sclerotial pathogens of onions and vegetable crops from soils and development of integrated approaches for sustainable disease control.

    Acknowledgments :

    There were many people and organisations that provided assistance to make this research possible. They include:

    • DPI personal Craig Murdoch and Slobovan Vujovic for assistance with technology transfer activities.
    • Peta Easton for technical assistance and Dr. Liz Minchinton for collection of survey data in NSW and SA.
    • John Hunt of Agrimm Technologies Ltd for his valuable advice on biocontrol trial preparation and Rob Stanic for arranging supply of Trichopel Ali52 and other products for field trials.
    • Doug Wilson and Paul Geister (NuFarm) for advice with fungicides and Elliott Chemical and Serve- Ag Research for supplying DADS for field trials.
    • Peter DalSanto (AgAware Consulting) for advice with fungicides and processing minor use permits for fungicide treatments.
    • Soheir Salib, Department of Primary Industries, Knoxfield for assistance in establishing and harvesting field trials and reviewing this manuscript.
    • The spring onion growers in Victoria who graciously allowed trials on their farms and provided assistance in their establishment, maintenance and harvest.
    • Agrochemical companies for providing samples of fungicides and other companies for supplying biological products for laboratory, glasshouse and field work.

    The authors thank the members of the Steering Committe, Rocky Lamattina, Tony Lamattina, Craig Arnott, Karl Riedel and others for their valuable advice to this project.

    This project was commissioned by Horticulture Australia Limited with funds frrom the Vegetable R&D levy..

    The Australian Government provides matched funding for all HAL’s R&D activities.


  • Doug Wilson and Paul Geister (NuFarm) for advice with fungicides and Elliott Chemical and Serve- Ag Research for supplying DADS for field trials.
  • Peter DalSanto (AgAware Consulting) for advice with fungicides and processing minor use permits for fungicide treatments.
  • Soheir Salib and other staff at the Victorian Department of Primary Industries, Knoxfield for their assistance in establishing and harvesting field trials and reviewing this manuscript.
  • The spring onion growers in Victoria who graciously allowed trials on their farms and provided assistance in their establishment, maintenance and harvest.
  • Agrochemical companies for providing samples of fungicides and other companies for supplying biological products for laboratory, glasshouse and field work.
  • The authors thank the members of the Steering Committe, Rocky Lamattina, Tony Lamattina, Craig Arnott, Karl Riedel and others for their valuable advice to this project.

This project was commissioned by Horticulture Australia Limited with funds frrom the Vegetable R&D levy..

The Australian Government provides matched funding for all HAL’s R&D activities.


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