- François-Xavier Branthôme
Europe institutes emergency regulations on ToBRFV
The Tomato brown rugose fruit virus (ToBRFV) will get a quarantine status (Q status), starting November 1. From that day on, a European emergency regulation will come into force, which includes that each case of the virus in Europe must be made public. The decision was made by the European Commission in July. For tomato and bell pepper, specific measures will apply, with introduction and movement of the virus in the EU being prohibited.
The allocation of a Q status to the ToBRF virus had been a matter of debate among virus experts for some time already, because taking strict measures doesn’t necessarily mean the virus will actually be eliminated. Destroying crops at companies affected by the virus is heavy-handed and costly – and the virus isn’t a danger to humans. This was a reason why the Netherlands Food and Consumer Product Safety Authority (NVWA) initially wasn’t a proponent of assigning a Q status.
Now, under pressure from several virus-free member states, a European-level decision was taken to assign Q status, in order to prevent the virus from spreading further. The successful elimination of the virus at infected German companies last year was taken into account when reaching this decision. In the Netherlands, a hygiene protocol is in place.
Obligation to report
The measures will be in force from November 1, both for bell pepper and tomato growers as well as breeding companies and young plant growers that work with one or both crops.
Growers will be under obligation to report. Upon infection with the ToBRF virus, they will have to report this to the NVWA in the Netherlands, or one of the designated organizations in other member states. Every member state then has the option to determine whether measures need to be taken upon discovery of the virus in production cultivation.
Since last summer, NVWA has been carrying out inspections in the Netherlands to look for ToBRFV, at the request of the European Commission. More than a hundred tomato and bell pepper cultivation companies have been visited so far, with no infections having been found. According to international plant health organization EPPO, both the Netherlands and Belgium have the status ‘ToBRFV-free’.
This could be considered questionable, however, because there’s no obligation to report yet in Belgium and the Netherlands. The NVWA responded to the EPPO reports: “There are indications of a possible presence in the Netherlands, but the NVWA has not been able to confirm this.”
Additional lab tests
For breeding and propagation companies, the Q status naturally applies as well. Tomato and bell peppers seeds will need to be free of ToBRFV or originate from ToBRFV-free areas, both before entering the EU and before coming on the market. Thus, lab tests are needed. Laboratories in countries where seeds come from, like Peru, can expect busy times ahead.
ToBRFV findings have been confirmed in countries including Italy, Mexico and Turkey in recent months. At a British tomato cultivation company in Kent, the virus was found in July. The greenhouse was emptied, and would remain so for 14 weeks. Tests in a Dutch laboratory confirmed that it was indeed the ToBRF virus.
A more recent report came in August from Arizona and California (see below). That particular report is not yet found on the EPPO world map update. Plant virologist Bob Gilbertson with UC Davis reported that ToBRFV was found on imported tomatoes from Mexico, where the virus has been present since 2018.
The emergency regulation are in line with the new European Plant Passport, coming into force December 14, where extra emphasis will also be on traceability of starting material.
ToBRFV found on imported tomatoes in California
First discovered in Jordan in 2015, ToBRFV moved on to Israel, Turkey, and Saudi Arabia, was spotted in Germany (2016) and Italy (2018) with likely occurrences reported (but not confirmed) in Chile, Ethiopia, Sudan, Thailand, Peru, China, and the Netherlands. Now it’s being reported as widespread in Mexican greenhouses, just a hop and a skip across the border into neighbouring states.
“We’ve had two incidents of it in California,” says Bob Gilbertson, who specializes in plant virology and seed pathology at University of California, Davis. “It was identified in a Santa Barbara County production greenhouse in September last year, confirmed by Kai-Shu Ling of the U.S. Department of Agriculture and by our plant pathologists. In that instance, all ToBRFV-infested and symptomatic plant material was voluntarily destroyed.
“Then, sometime in early August, we received suspect fruits from a market in Sacramento that had obtained them from Baja, Mexico,” he said. According to a report by Gilbertson and Zach Bagley of the California Tomato Research Institute, “They didn’t have necrotic lesions on the fruit --- there were white blotches --- but when we tested them, ToBRFV showed up.”
Available information to date suggests ToBRFV is primarily a threat to protected culture (greenhouse) production although outbreaks in open fields have been reported in Mexico. Because they grow more than 90 percent of the nation’s processed tomatoes but don’t grow for the fresh market, the California Tomato Growers Association is keeping a watchful eye on the situation, but suggests the greater concern belongs to the Western Growers Association.
The acronym for tomato brown rugose fruit virus represents a new species of a well-known group of plant viruses, tobamoviruses. It’s highly virulent and seems to override existing genetic controls and researchers are noting: “Because of the rapid spread of this virus, it represents a major concern for worldwide tomato production because no tomato varieties are known to be resistant to it as it breaks or is not recognized by Tm-2 2 or any other resistance gene currently used to protect tomatoes genetically against tobamoviruses.”
Pathologist Gilbertson emphasizes the speed of the spread factor. “There is no insect vector here. It’s solely transmitted by contact, human touch or machines or tools. It’s extremely stable and can survive in dry tissue for years.”
Steam sterilisation unit developed to fight ToBRFV
The CambridgeHOK company (www.cambridgehok.co.uk) is giving hope to the tomato growers with an innovative solution it has devised alongside one of the sector’s biggest producers. The company, which is based in East Yorkshire (UK), has designed and built a steam sterilisation unit which is helping minimise the risk of spreading ToBRFV and protect future crops.
Ross Hibbs, commercial director of Cambridge HOK, explained: “ToBRFV is a huge problem for tomato growers. It has the potential to devastate crops very quickly and it can remain in leaf debris, seeds and soil for months, meaning it is incredibly difficult to get rid of. […] It is easily passed between glasshouses and between sites, so unsurprisingly, producers are keen to develop new solutions that will effectively control the virus”.
Mr Hibbs said one of the major challenges is that ToBRFV is able to survive outside the host plant, meaning it quickly spreads via contact with plant trays and crates, and other equipment. Another issue for the company was that the virus has a tough outer wall, making it impervious to standard chemical treatments.
Phil Pearson, group development director at APS Group, in front of the CambridgeHOK designed and built steam container.
CambridgeHOK built the unit out of a shipping container, in which all the packaging, plant trays, crates and other equipment used glasshouses are now sterilised at 95°C for five minutes before each use, to ensure the virus cannot spread. The company said high temperature treatment was the best way to ensure the risk of virus infection was eliminated.
Source: hortidaily.com, Western Farm Press