Figure 1: Stem necrosis on capsicum. Photo gd.eppo.int

In August 2024, tomato brown rugose fruit virus (Tobamovirus fructirugosum, or ToBRFV) was confirmed to be present in commercial production sites in South Australia.

Seed tracing investigations have led to a positive result for tomato brown rugose fruit virus in two seedlines which were imported into Australia from Türkiye in late May 2024. These seedlines had offshore testing certification, with negative results for this virus. To date, the Türkiye seeds have not been confirmed as the source of the outbreak, and further testing is in progress.

As a precautionary measure, seed testing certification issued by laboratories in Türkiye has been suspended by DAFF and the import pathway is being reviewed. Tracing activities are also being conducted on imported seedlots.

Tomato brown rugose fruit virus

Tomato brown rugose fruit virus is on the National Priority Plant Pest list and regarded as a considerable threat to Australia’s vegetable and nursery industries due to reduced yield and quality of produce

Marketable yield losses of between 5-55 percent have been reported. The number of fruits per branch may also be reduced.

It is a highly contagious plant virus that is known to infect tomato, capsicum and chilli. A number of weeds, such as nightshades, fat hen, quinoa (Chenopodium) and buffalo bur are also known to be infected. Potatoes are not known to host or be affected by the virus.

How do I know if there is ToBRFV in my crop?

ToBRFV is named after the characteristic brown wrinkled (rugose) patches that can develop on infected fruit or plants. Symptoms may vary depending on the variety, time of infection, plant age and environmental conditions, in particular temperature and photoperiod (day length).

Common symptoms include:

• Mosaics (chlorotic or pale patches) developing on younger leaves in the head and side shoots.
• Leaves may be crumpled (puckered) and deformed; in some cases, leaves may be narrowed.
• Brown (necrotic) streaks may develop on stems (Figure 1).
• Fruit can develop chlorotic marbling, which can appear similar to infection with Pepino mosaic virus (Figure 2).
• Fruit may develop brown wrinkled (rugose) patches (Figure 3)

A reduction in root biomass in the early stages of infection has also been reported as hormone imbalances impact on lateral root development. Note that foliar symptoms may be confused with other tomato viruses that result in similar symptoms.

Minimising the risk

Figure 2: Chlorotic marbling on capsicum. Photo gd.eppo.int

ToBRFV spreads easily through contaminated tools, hands, clothing and direct plant to plant contact, including grafting and cuttings. The virus can spread easily to all plants in a crop.

It can also be transmitted in seeds and irrigation water. ToBRFV is highly stable and can remain viable in seed, plant waste and contaminated soil for several months.

Below are some recommendations to reduce the risk of entry and spread of ToBRFV.

• Restrict access to production sites to staff, and limit movement between facilities. Growers can sign up to Onside for free to manage farm visitors: getonside.com/au/ausveg
• Train staff to recognise plant disease symptoms and pests and hygiene measures.
• Monitor your crop regularly for symptoms. If you’re not sure, send a sample to a diagnostic laboratory to confirm.
• Prohibit consumption of susceptible hosts (tomato, capsicum, chilli) on site.
• Remove wild tomato plants and other weed hosts that could act as reservoirs for the virus.
• Change or wash clothing and footwear when entering the production site or use disposable clothes and booties. Wash your hands or change gloves regularly.
• Disinfect tools and equipment.
• Contact your seed suppliers to seek their assurance about what specific testing has been applied to batches of seeds.

What to do if you see unusual symptoms

Report any unusual plant pest or disease by calling the Exotic Plant Pest Hotline on 1800 084 881.

To learn more about ToBRFV and the current outbreak visit the PIRSA website.