Research shows: ozone kills ToBRFV in drain water

Disinfecting drain water with ozone very effectively eliminates the presence of Tomato Brown Rugose Fruit Virus (ToBRFV). This is the conclusion of Groen Agro Control after research in its laboratory. The news is a boost for tomato growers and plant breeders. They can use this disinfection method to eliminate a risk factor for spreading the feared virus and safely reuse their drain water after disinfection.

ToBRFV is a tobamovirus that can cause severe symptoms in tomato plants. The virus can spread both mechanically (through people and tools) and through contaminated drain water in tomato crops. When recirculating drain water, it is therefore important that ToBRFV is killed off during the purification step.

At the request of Agrozone, which develops ozone installations for horticulture and industry, Groen Agro Control from Delfgauw, the Netherlands investigated whether ToBRFV in drain water survives treatment with ozone.

Trial design
Agrozone and Groen Agro Control have set up the test according to the standard settings as the ozone installations of Agrozone function in practice, a realistic practical test. The disinfected water was then used to inoculate five tomato seedlings. As a positive control, a treatment was also performed with non-disinfected drain water containing the virus. Both treatments were performed in two replications.

After two weeks, the uninoculated leaves in the head of the plants were sampled and tested for the presence of ToBRFV using an ELISA test.

Results
In the series with the untreated drain water (the positive control), ToBRFV infection was detected in four of the five inoculated plants in both replicates. The ozone-treated drain water did not result in infection in any of the five inoculated plants in either repetition. This means that no virulent virus was present in the treated water anymore. In other words, the virus did not survive the ozone treatment.

Good news
According to Roy Imming of Agrozone, ozone treatment is the first disinfection method that has been proven effective against ToBRFV. "That is one of the many advantages of ozone, no virus can survive against it. It's good that this has again been officially confirmed by an accredited lab, that's positive news for growers. We can also make a direct connection between the setpoint of our installations and the killing off of the virus. This can be adjusted and even remotely monitored so that abnormalities and risks can be spotted in time. Should virus end up in the drain water from a local source of infection, you can use an ozone plant to disinfect and reuse it in a responsible and controlled manner."

For more information:
Groen Agro Control
Distributieweg 1
2645 EG Delfgauw
The Netherlands 
www.agrocontrol.nl/en