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Katunga Fresh update

Australian growers stunned by ToBRFV greenhouse clearance

After the Australian company Katunga Fresh detected ToBRFV in a special quarantine greenhouse for young plants, cultivation at the entire facility was immediately halted according to Australian government protocols. This decision surprised international experts who have seen in recent years that it's better to cultivate with the virus than against it. "You can't stop this virus."

Peter van den Goor himself is no longer sure what to think. Instead of overseeing cultivation, checking harvest forecasts, and watching trucks full of tomatoes leave the Australian greenhouse company Katunga Fresh, he and his colleagues were this week handing out job vacancies to their former employees. All of them were laid off—there is simply no work for them anymore. This is due to the detection of ToBRFV at their nursery. The virus was found in a number of young plants that were still in quarantine at the nursery, awaiting placement in the greenhouse. According to the strict requirements of the Australian government, this led to the removal of the entire greenhouse, which contained 21 hectares of tomato plants. In Australia, a large-scale detection effort is currently underway for infected plants: Over the past few days, more than 2,000 plant samples have been tested from 84 greenhouses across 18 companies. Three cases of the virus have been confirmed, and three more samples are being tested due to potentially contaminated seed. The sector is holding special meetings—digitally—to try to prevent such consequences for other nurseries that may be affected by the virus.

ToBRFV, or Tomato Brown Rugose Fruit Virus, was first observed in a tomato crop ten years ago and spread worldwide from Jordan and Israel. Australia seemed to escape the virus for a long time but had its first outbreak last year. The virus was found on three farms in the Northern Adelaide Plains, South Australia. According to PIRSA (Department of Primary Industries and Regions), the greenhouses were cleared. However, this year, it has happened again. The greenhouse company Katunga Fresh, located in Victoria, over 700 kilometers away from the previously affected region, received young tomato plants in December. These plants were placed in quarantine according to the specially developed ToBRFV protocol. When they were later found to be infected with the virus, the company was forced to remove everything from the facility.

Katunga Fresh greenhouses (source)

Measures
At the company, they are stunned. Not only have they been kept in uncertainty for weeks about what to do, and there's still much unclear about the next steps, but the impact of these measures is enormous. Financially, but also on a human level. Katunga Fresh had been invested in by the investment company Centuria last year, but the nursery is fundamentally a family business with deep roots in the local community. Many of the workers who were laid off had been with the company for years and had stayed on even through the COVID-19 pandemic. Moreover, it's difficult for the growers to accept that Australia is sticking to measures that are more drastic than anywhere else, while the rest of the world is learning to cultivate with the virus. For example, in Europe, the virus was removed from special quarantine status as of January 1 of this year, meaning the reporting obligation and certain mandatory actions following detection were lifted.

"At the initial discovery of the virus in the Netherlands, they also discussed emptying greenhouses, and that did happen at first. This was when the virus was just beginning to spread in the Netherlands, in 2019," says Jasper Verhoeven, hygiene expert at Royal Brinkman, who foresaw that Australia would need to learn to live with the virus after the first outbreak. "But with today's knowledge, techniques, and research, it's usually better to investigate the issue, specifically determine what the problem is, and act accordingly. In recent years, we've learned that it can be present on surfaces, in water, and even in the air. It remains active for years and spreads easily. But just because it's present doesn't mean it will infect the plant or cause spreading. And even if there are no visible outbreaks in the crop, it doesn't mean the virus isn't there."

What Jasper is talking about is the virus pressure. The level of this pressure, combined with the plant's health and the virus's ability to penetrate the plant, ultimately determines whether the virus will manifest. "So, in short, you want to reduce the virus pressure and increase the strength of the plant," Jasper summarizes.

Presence
At Enza Zaden, they also emphasize the importance of virus pressure over simply detecting the virus. It's now clear that the virus will eventually be present everywhere—even on an island like Australia, which is known for its strict phytosanitary measures and the large distances between farms. "The world is small when it comes to viruses," confirms Martijn van Stee, Crop Breeding Manager for Tomatoes at the breeding company. Enza Zaden has conducted extensive research on the virus in recent years and invested heavily in developing resistant varieties. Martijn mentions that all high-tech horticultural regions have had to deal with rugose in recent years. "We always say: It's not a question of if it will come, but when. Australia was one of the last high-tech cultivation countries where it hadn't yet been reported."

How did it get there? Probably through human activity, says Martijn. "Imported products can carry the virus, but Australia imports very little and has strict import regulations for consumers. This also applies to the import of seeds, for which Australia has even stricter rules than many other countries. So, humans are the biggest and most likely vector. We know what the virus can attach to and how persistent it is. It doesn't break down quickly." Like Jasper, he is convinced that the virus cannot be eradicated from Australia.

Preparing for an outbreak
But what then? How does a country protect itself against an outbreak? Should all greenhouses where the virus is found be cleared? At Katunga Fresh, the issue specifically involves an infection in young plants in a separate compartment, not in the entire nursery. However, even if an infected plant is found in the middle of a greenhouse, Enza Zaden advises against clearing the entire operation. "First of all, that's not for us to decide, it's a business decision," Martijn responds firmly. "We do advise ensuring that other compartments don't become infected by isolating them and preventing people, products, and materials from moving from one compartment to another. And you need to be extremely strict with hygiene." In the case of a rugose infection, it's likely that part of the crop will need to be abandoned. "We recommend doing thorough cleaning during the crop changeover. As a seed company, this seems like logical advice, but from international research, we also recommend choosing resistant varieties. Combined with good hygiene, this is the way to lower virus pressure." And that's the key. "The virus is present, but the higher the virus pressure, the greater the chance of contamination, mutations, and further complications."

Martijn showed last year that the HREZ gene from Enza Zaden and the Tm-22 gene are very similar.

At Enza Zaden, the focus is exclusively on highly resistant varieties. "Only with highly resistant varieties is the virus not able to multiply. With other types of resistance, you don't see symptoms, but the virus can still be present in high quantities." He compares this to TYLCV (Tomato Yellow Leaf Curl Virus), where the resistant varieties don't show symptoms, but the disease pressure is often still high. "I understand that for a grower, the absence of symptoms might be enough when it comes to rugose, but the virus can still thrive. That makes it more complicated. That's why we are convinced that only highly resistant varieties are the solution, combined with strict hygiene. This way, the virus pressure will ultimately decrease to a level where it no longer causes plant contamination."

Impact on the industry
Jasper certainly understands the unrest in Australia: Australian media are reporting losses of 70% to 100% of the harvest, severely damaging the entire multi-million dollar industry. And he acknowledges that this is definitely a possible scenario—if nothing is done. "But many other plant diseases have the same effect, and you don't take such drastic measures for them. A virus doesn't mean the death of a greenhouse. The more severe the infection, the greater the consequences, but we also see that the crop can survive it." This is similar to, for example, cucumber mosaic virus. "In fact, it's true for many viruses—those that affect people as well. With strong resistance, you are less sensitive to it. But you can't avoid it, because the rugose virus is already out there. Not just where it has been found, but in many more places. What you can control is how easily you allow infection in: the door can be wide open, slightly ajar, or just a ventilation gap."

In recent months, he has already seen that interest in virus-resistant products and measures has grown in the Australian sector, whether it's protocols, hygiene products, or other solutions. At Enza Zaden, there's been interest in resistant varieties, and many trials have been conducted. "No doubt other seed companies have seen the same. Growers are already preparing and learning."

Insurance
"Scout, and take measures," continues Jasper when asked what to do in case of infection. "Properly instruct staff. The more you can clean, the better the chance you'll literally wash away the virus or at least dilute it. Removing the source of the virus also reduces the viral particles. And by choosing plant-strengthening measures, you can make the crop less susceptible to infection." These are examples of measures that Royal Brinkman incorporates into their Horti Hygienz concept, which helps growers set up the right protocols to prevent infection. "It's about finding a balance between the measures and their effects: what barriers do you put up to protect yourself from virus pressure, and how do you reduce the virus pressure itself? What investments do you make in this? It's like taking out insurance."

Horti Hygienz Concept by Royal Brinkman

This approach is very different from clearing entire businesses, which Martijn says he also struggles with from a grower's perspective. "I understand that fear drives the action. Clearing might seem like a logical solution to get rid of the virus, but it doesn't help anyone, and it doesn't necessarily lower the virus pressure. The question remains: How well do you clean the greenhouse, and what do you do with the waste? Clearing alone won't solve the problem. You need to ensure the virus doesn't spread outside, and that you don't create a source for your neighbor. Preventing spread is the most important thing." It's a difficult issue for a government, but at the same time, he sees that a lot of knowledge has been gained in recent years.

For instance, the Dutch NAKtuinbouw (the Dutch Inspection Service for Horticulture) stated last autumn that the virus is now present almost everywhere in the European Union, and it has proven impossible to eradicate the virus. That's why, on a European level, it was decided to end the emergency measures for ToBRFV and classify the virus as an RNQP (Regulated Non-Quarantine Pest) as of January 1, 2025. This means, for example, the reporting obligation was removed. Jasper confirms that this decision has brought relief to growers. "Such a reporting obligation causes anxiety and panic among growers, which can lead to the virus being kept under wraps. Especially when you see the measures being taken, a business won't openly report it, and certainly won't test in suspected cases." Even with the Q-status in place, there was little reporting of rugose infection in Southern European countries over the past years. "I understand the policy and the desire to be strict, but that can actually encourage the spread and cause more problems than a policy where a business is put on hold, followed by further research, measurements, and open discussions to reach the right solution. Listen to all parties, to the experts. And I hope they can offer an open way of communicating and a well-thought-out structure to guide growers."

For Katunga Fresh, this won't make a difference anymore. The consequences for the future of the nursery are still unclear. The Australian government has opened an emergency fund, but Katunga won't be the only nursery affected by the infection and its economic fallout. Still, the nursery, along with others in the Australian sector and the PCA (Protected Cropping Australia), is intensively lobbying to have ToBRFV removed from Australia's quarantine list and to have the virus classified as "manageable." The question growers are asking is how much pain the industry has to endure before they reach that point.

For more information:
Royal Brinkman
[email protected]
www.royalbrinkman.com
www.royalbrinkman.com/hortihygienz

For more information:
Enza Zaden
+31 (0)228 350100
[email protected]
www.enzazaden.com