Abstract
<jats:p>Three Austrian tomato production sites, which were considered ToBRFV-infected in 2022, were monitored analytically for ToBRFV over two growing seasons (2023 and 2024). The production sites produced established, non-ToBRFV-resistant tomato varieties and new varieties that had been described as resistant to ToBRFV. The project results show that many of the new tomato varieties are not resistant to ToBRFV, but rather tolerant. It has also been shown that tolerant varieties can be sufficient to significantly reduce the viral load during a production season in a ToBRFV-contaminated environment if there are no non-resistant plants in the immediate vicinity and if hygiene measures are stringent. Production data from tomato growers indicate that a virus outbreak leads not only to yield reductions but also to substantial additional expenses. These costs span multiple areas - including the disposal of infected plants, cleaning, hygiene measures, personnel costs, higher costs for seeds or plantlets of new resistant varieties-and are incurred not only during the outbreak year but also in subsequent years. Wastewater samples (SARS-CoV-2 wastewater monitoring at TU Wien) from Austrian wastewater treatment plants located between Vorarlberg and Burgenland were tested for ToBRFV between April 2020 and December 2024. ToBRFV was clearly detected in all samples. Thus, ToBRFV was already detected in wastewater samples taken before the first officially confirmed outbreak in Austria. ToBRFV was detected using real-time RT-PCR in compost produced through hot-rot and composed solely of plant waste from a farm infected with ToBRFV. Trials were conducted using the compost mixed with substrate soil. Although the transmission of the virus from the compost to tomato plants could not be verified, it also cannot be definitively excluded.</jats:p>