Tomato Brown Rugose Fruit Virus (ToBRFV)
Tomato Brown Rugose Fruit Virus (ToBRFV) is a plant virus that causes severe crop losses (up to 75%) in tomatoes, but also in peppers (capsicums and chillies). As with many other plant viruses, Integrated Pest Management techniques have been largely unsuccessful in addressing ToBRFV. This means best practice in horticulture isn’t helping and there are no known sprays or treatments to limit the disease. For the moment, Australia’s best defence is to eradicate any outbreaks, and use extensive quarantining.
Primary causes of transmission are contaminated seeds, and physical transmission, including pollinating insects. It is a robust, persistent virus, surviving away from its host for a long time (months) without loss of virulence. The industry is looking at developing new strains of tomatoes that are resistant to the virus. At this stage all cultivars of tomatoes bred before 2022 are susceptible to ToBRFV.
This highly infectious virus has rapidly spread from the Middle East (first known location in 2014), across Europe, China, North America, and parts of central and southern America. Until 2024, Australia had been able to isolate itself from this virus, however three cases have now been confirmed in South Australia. There has been a swift and comprehensive response to this, but it is sensible for the home gardening community to be made aware of this disease and what to look for.
Identifying the disease
The first hint that you may have an issue will probably show up in young leaves. These will show mild to severe mosaic symptoms (see photo) with deep green bulges/blisters, yellowing veins, deformed, narrow leaves, and smaller than expected leaves. The entire plant may be stunted, failing to thrive. The severity of the symptoms can vary depending on time of infection, environmental conditions and how susceptible that cultivar is.
Once the fruit starts to form – inspect the calyx (the outer green structure that surrounds the petals where the fruit attaches to the stem), it can look to be drying out and going brown – especially at the tips. Fewer fruits are formed.
Fruits fail to ripen. They are pale, streaky, or with spotty yellow blemishes (see photo above). These can develop further into brown spots and then necrotic lesions (hard brown spots and flecks). Fruit can sometimes wrinkle and will often feel rough to the touch. Tomatoes can show these symptoms early on, or they can start off looking normal and develop these symptoms later.
In peppers, leaves will show puckering and mottling, plants are stunted, and fruits show wrinkled yellow to brown patches followed by necrotic spots and can be deformed.
What to do?
A number of different viruses affect tomato and other Solanaceae crops in Australia and some have similar symptoms to ToBRFV, so correct identification is important. A useful fact sheet about crop viruses, how they spread and management options (which usually involve destroying infected plants) can be found here.
Given the highly contagious nature of this disease, if you are suspicious that your plants have ToBRFV, don’t bring them into your local nursery for identification and potentially spread the virus around, call the Pest Plant Hotline on 1800 084 881 and follow their advice. If they ask for photos – send good quality, high resolution pictures. This virus has the potential to wreak havoc on our tomato and pepper growing industries, as well as home gardens, community garden plots etc. Remember it is incredibly contagious; if you are concerned, don’t go to other gardens until you get the all clear.
Eliminate any potential weedy host plants, like the nightshade family.
It is always good practice to regularly disinfect your gardening tools. Keep in mind that this virus lasts a long time off the host plant, so disinfecting practices are important. Use a solution that is 1 part liquid pool chlorine (this is usually in a 12.5% solution) to 100 parts water (a 1% solution).
