Greenhouse Canada

WEBINAR: Keeping out the rugose

March 24, 2020  By Greta Chiu

Watch the recording

Date: April 28, 2020, 2pm ET

Webinar description:
Since its first sighting in 2014, the tomato brown rugose fruit virus (ToBRFV) has been found in different parts of the world. Learn about its symptoms and pathways for transmission. Take these preventative measures and enhance the biosecurity of your greenhouse.

Speaker: Cara McCreary, Greenhouse vegetable IPM specialist, Ontario Ministry of Agriculture, Food and Rural Affairs

Sponsored by: 

About the speaker:

Cara McCreary
Greenhouse vegetable IPM specialist,
Ontario Ministry of Agriculture, Food and Rural Affairs

Cara McCreary is the Greenhouse Vegetable IPM Specialist with OMAFRA and is working out of the Harrow Research Centre. Cara joined the ministry in January, 2015 from a position as a Research Associate in the Edible Bean Program at the University of Guelph Ridgetown Campus. Prior to joining the University of Guelph, Cara spent 6 months as the Acting Field Crop Entomologist in the Agriculture Development Branch. She also has several years of experience as a greenhouse scout and supervisor and as a horticultural advisor. Cara has a Master of Science in Environmental Biology from the University of Guelph, a Bachelor of Commerce in Business Administration from the University of Windsor and an Associate Diploma in Horticulture from the University of Guelph. During her Master’s degree, she studied the life cycle, temperature-dependent development and economic impact of an agricultural pest, the bean leaf beetle. Pest management has been her focus and passion through both work experience and education.

Additional questions answered:

  1. Do the temperature treatments affect the viability of seeds?

Heat treatments used directly on seed could affect the viability depending on temperature and plant species. There are currently no published recommendations for temperature seed treatments against ToBRFV. The study that was presented here, was referring to hot water treatment applied to picking crates and reference was made to pasteurizers used to treat irrigation water.

  1. Do peppers show no or reduced symptoms that could cause asymptomatic transmissions?

Any plant or variety (pepper or otherwise) that has tolerance to ToBRFV could be asymptomatic and act as a reservoir contributing to further transmission to susceptible plants or varieties.

  1. Which is the best disinfectant against ToBRFV?

Several researchers across the globe are evaluating disinfectants.  As the work is ongoing, there are currently no official recommendations available.  For Canadian producers, check Health Canada’s Pest Management Regulatory Agency (PMRA) label search engine (link below) for registered products and active ingredients before using in your greenhouse.

  1. Do you know what rate of Virkon was used on picking crate trials?

In Dr. Adrian Fox’s research trials, 1% Virkon was used to test on picking crates.

  1. What is the TSP (disinfectant)?

TSP (or TSoP) stands for trisodium phosphate and is an inorganic compound producing an alkaline solution that has been used as a cleaning agent or disinfectant.

  1. For crates, is bleach still an option as previously recommended for killing of this virus?

Several researchers across the globe are evaluating disinfectants.  As the work is ongoing, there are currently no official recommendations available. (same answer as #3)

  1. Have there been any known benefits in using chlorine dioxide in low dose (2-3 ppm) to kill rugose?

I have not seen any data on this use.

  1. Can tell us more about the soap or medicated soap? What are components in soap and their concentration?

In Dr. Adrian Fox’s research trials, the medicated soap was HiBiSCRUB, antimicrobial skin cleanser – which contains Chlorhexidine Gluconate 4% w/v.

  1. If there is soap present, does this affect the length of time in killing the virus?

It is usually best to ensure there is no soap residue on a surface when applying a disinfectant as soap can inactivate the disinfectant.

  1. Does the non-fat milk work on this virus?

In Canada, non-fat milk is not approved for this use and concerns have been raised about the allergenic potential.  Historically it has been recommended for other viruses, though research indicates variable results depending on the concentration, surface, contact time and virus.  Some researchers, including Dr. Ling (USDA), have evaluated this for use on tools against ToBRFV, though results have not been published yet.

  1. IS UV light considered for the disinfection and elimination of the viruses?

I have not seen any data on this use.

  1. Any signs of the tomato brown rugose fruit virus in the Ontario 2020 crop? If so, what is dollar loss of crop?

I am not aware of positive cases in Ontario’s 2020 crop.

  1. Has the virus been detected in tomato field crops?

There is limited information about detections in field tomato crops, though there have been reports in some countries.  Because it is mechanically transmitted, field producers, especially processing tomatoes, are much less likely to experience a high rate of transmission due to the limited contact of workers to plants.

  1. Is there a list of accredited labs in Canada available for testing ToBRFV?

There is currently no Canadian Food Inspection Agency accreditation program for ToBRFV testing. However, if a Canadian facility suspects the presence of the pest, they should contact their local CFIA office to arrange for confirmation testing.

Alternatively, there are private and provincial plant health labs accredited under the Standard Council of Canada to perform test lab services including testing for the detection of ToBRFV. Agricultural ministries or grower organizations may be able to assist with identifying accredited laboratories for specific locations.

  1. Do you think a vaccine type of treatment will be developed?

There are several researchers across the globe working on developing a vaccine.  The necessary research and regulatory review could take up to 18 months. Vaccines have been successfully commercialized against other plant viruses.

  1. Has Dr. Adrian Fox and the other researcher published their research? Is there a way I can read the details? What was the name of the other researcher?

Dr. Adrian Fox’s work is ongoing, and when complete he plans to publish in scientific journals.  In the meantime, he has been providing online updates as available (see link below).

Several other researchers including Dr. Aviv Dombrovsky (Israel) and Dr. Salvatore Walter Davino, Dr. Stefano Panno (Italy) were mentioned.  Their work is ongoing, and some completed studies have been published in scientific journals. 

  1. Do crop rotations work?

This could be a viable strategy so long as the rotated crop is not a host and the greenhouse is properly equipped to deal with a different crop (i.e. do they have the right equipment).  Be mindful that we may not have the full picture of ToBRFV host range yet, and several common greenhouse crops (e.g. such as pepper, eggplant) are also solanaceous and are potentially either susceptible or carriers.  Options for rotation may be limited to crops such as cucumbers, lettuce or strawberries.

  1. Should growers avoid congregating at coffee shops or other spots?

This may not be necessary if proper precautions are taken. Just be sure to thoroughly wash your hands and change clothes after leaving the farm and going out in public AND after returning to the farm.

Don’t miss the second webinar in this series:
Dealing with rugose at the border with Michael Bledsoe of Village Farms. Watch the recording now.