Tomato Brown Rugose Fruit Virus (ToBRFV) continues to be found in more countries, but luckily Canada is not yet among them.
Within the first few months of 2019, it transferred to Germany, Mexico and Italy. It has also been previously found in California, and the first outbreaks were found in Israel in 2014 and Jordan in 2015.
The virus has no products for treatment once detected.
Why it matters: If the virus enters Canada, it will pose a problem for farmers because there are no protocols for treatment. Biosecurity is of upmost importance to reduce the spread.
Tomatoes and peppers are the main host of the ToBRFV.
This type of virus is known to be very stable and survives for long periods of time on surfaces. It belongs to the Tobamovirus genus, a persistent, highly transmissible group of plant viruses and can cause substantial crop losses.
“Reports of crop losses range from 10 to 15 per cent where the virus was diligently managed to 100 per cent where the virus went undetected or the crop was removed,” says Bianca Jamieson, spokesperson for the Ontario Ministry of Agriculture, Food and Rural Affairs.
ToBRFV is thought to be transmitted similar to other Tobamoviruses, via seeds and mechanically.
“One distinguishing characteristic of ToBRFV is its ability to overcome all known genetic resistances to other related viruses in tomatoes including the Tm-22 gene and causes severe fruit symptoms,” says Jamieson.
The symptoms of the virus vary depending on the varieties of the fruits, but commonly include chlorosis, mosaic and mottling. As well, it can be seen in the occasional leaf narrowing, necrotic spots on the peduncles, calyces and petioles. The symptoms can affect the fruit also with yellow or brown spots, and rugose symptoms, deformed or irregular maturation.
Jamieson says that within a transplant nursery, producers are encouraged to do the following to help decrease the chances of spreading the virus:
- Inspect transplants, especially before grafting (if used) weekly for visible symptoms of ToBRFV; although symptoms may not be visible.
- If infected plants are detected, eliminate all plants within a minimum of 1.5 metres beyond the outermost symptomatic plant as these plants may also be infected without showing symptoms.
- Do not touch other surfaces during the plant removal process. Cutting off irrigation to the plants that are to be removed a day before the process will result in a lower risk of sap transfer and infection spread.
- Once the plants are removed, dispose of them via incineration and sterilize or destroy all plant trays that contained the infected plants.
- Always visit the infected greenhouses last.
Jamieson says that during cultivation producers are encouraged to do the following:
- Only enter with clean clothes and shoes. It is suggested to use protective clothing that will stay in the greenhouses.
- Thoroughly clean and disinfect the greenhouse at the end of a crop season along with cutting tools, equipment and other implements, pallets and baskets after every use.
- Note that clothes can be contaminated while eating tomatoes at home or through exposure at infected nurseries and greenhouses.
“Producers are encouraged to practice strict sanitation and disinfection of workers’ clothing, equipment, tools etc.,” says Jamieson. “We always encourage producers to observe biosecurity preparedness. The Canadian Food Inspection Agency is monitoring the situation.”
If symptoms are found, contact Amanda Tracey at [email protected].