Chemotherapy of Tomato Mosaic Disease using Ribavirin and 8-Azaguanine

Tomato mosaic disease (ToMD) caused by Tomato mosaic virus (ToMV) is a major threat to tomato production globally. In Pakistan, tomato is one of the most popular vegetables, and ToMD causes significant losses in fruit production, quality, and size. Various management strategies are implemented to control the disease. In this study, the efficacy of chemotherapy using ribavirin and 8-azaguanine was investigated. Seedlings of tomato plants were inoculated with sap from symptomatic tomato plants using the sap transmission technique to test the pathogenicity of the virus. Disease incidence and severity were recorded at weekly intervals for one month after inoculation. Ribavirin and 8-azaguanine were applied to tomato plants at different concentrations, and disease incidence and severity were observed weekly for one month after treatment. The results showed that the mechanically inoculated plants exhibited characteristic symptoms of ToMD, such as a mosaic pattern of color on the leaves. The disease incidence did not reduce with the application of ribavirin and 8-azaguanine, but the severity of the disease was significantly reduced. The plants treated with 1000 µM of ribavirin and 8-azaguanine had significantly lower severity scores compared to the untreated plants. However, the treated plants did not recover from the disease. The study found that ribavirin and 8-azaguanine are effective chemotropic agents in reducing the severity of ToMD, although they cannot cure the disease completely. Further studies are required to investigate the underlying mechanism of how ribavirin and 8-azaguanine suppress the symptoms of ToMD