Chlorine Dioxide: Antiviral That Reduces the Spread of ToBRFV in Tomato (<i>Solanum lycopersicum</i> L.) Plants

Tomato brown rugose fruit virus (ToBRFV), being a mechanically transmitted disease, is usually difficult to control; therefore, an effective alternative to reduce transmission and replication in the crop is by spraying with chlorine dioxide (ClO₂) during routine crop management. In this research, the efficacy of chlorine dioxide (ClO₂) for ToBRFV management in a greenhouse and open field was determined. The phytotoxicity of ClO₂ and its effective concentration against ToBRFV in <i>Nicotiana longiflora</i> plants were evaluated. Subsequently, the effect of ClO₂ on ToBRFV was evaluated in tomato plants grown in an open field. Finally, the effectiveness of ClO₂ on plants inoculated with ToBRFV under greenhouse conditions was evaluated and the number of necrotic local lesions (NLLs) was quantified. The results revealed that ClO₂ at 760 mg L⁻¹ did not show phytotoxicity and reduced the number of NLLs in <i>N. longiflora</i> plants. It also decreased ToBRFV transmission and replication in field- and greenhouse-grown tomato plants, improving agronomic parameters. ClO₂ reduced replication in plants inoculated with different amounts of ToBRFV inoculum in a greenhouse. <i>N. longiflora</i> leaves expressed lower numbers of NLLs when inoculated with ClO₂-treated tomato plant extracts. Finally, the results demonstrate that ClO₂ represents an effective management alternative when used by direct application to plants. To our knowledge, this is the first study where the use of an antiviral compound is carried out under field and greenhouse conditions.