Tomato growers in several countries have in recent years had problems with this new tomato virus, which was first found in Israel in 2014. "The virus is called Tomato brown rugose fruit virus (ToBRFV)", says virologist Dag-Ragnar Blystad in NIBIO.
The virus has now spread to both the United States and several European countries. It is very stable and contagious, and once it has entered a tomato garden it is difficult to get rid of. The virus causes damage to the tomato fruits, it can kill entire plants and can consequently cause large loss of income for tomato nurseries.
A monitoring program
Researchers at NIBIO have assessed that the probability of an outbreak is very high. Therefore, the Norwegian Food Safety Authority has granted a monitoring and mapping program for tomato brown spot virus in Norway in 2021. The Norwegian Food Safety Authority will take samples of tomato plants, and researchers at NIBIO will analyse them. From January to March, at least 250 samples were to be collected from the production of small plants in the tomato production. In August, 150 samples will be collected from greenhouses where tomatoes are produced.
Resistance to other viruses no guarantee of immunity
The Tobamoviruses only attack plants, but some of them are so common that they are found in almost all smoking tobacco, for example. The most common tobamoviruses in tomato are tobacco mosaic virus (TMV), and tomato mosaic virus (ToMV). Today's tomato varieties are bred to be resistant to these two viruses. Therefore, we have not seen attacks of these in Norwegian tomato greenhouses since the early 1980s. The new virus, on the other hand, is not stopped by the resistance to TMV and ToMV.
Norwegian tomato production is a growing industry. In 2020, more than 12,000 tonnes of tomatoes were worth more than NOK 400 million, according to the Green Producers' Cooperation Council. Calculations from NIBIO also show that it is more environmentally friendly to produce the tomatoes in Norway than to produce them further south in Europe and transport them here. The new virus therefore represents a great potential for damage. "If there is an outbreak in one or more Norwegian nurseries, the losses, and thus the compensation amounts, can amount to between 10 and 100 million, depending on the extent," Blystad says.
Consequences for the tomato industry
"Attacks of tomato brown spot virus in tomato production are very serious and can mean large financial losses for the gardener. After the attack, the tomatoes will most likely no longer be marketable. At the same time, asymptomatic plants are common. Therefore, all plants must be destroyed and the greenhouse plant decontaminated", says Emilie Sandell, specialist responsible for vegetables, fruit and berries in the Norwegian Gardeners' Association.
Sandell says that strict hygiene and preventive measures are the only way to fight the virus.
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