Vegetable crops account for about 4–5% of global agricultural production volume and are indispensable for the agricultural economy. Like any other plant, these crops are also vulnerable to a variety of viral infections. Unfortunately, treating these viral diseases remains a major challenge with no specific cure. Once infected, plants typically show symptoms such as leaf distortion, stunted growth, lower yield, and eventually crop failure, resulting in significant financial losses to the farmers. Early and regular diagnosis is therefore essential for maintaining healthy crops. Recently, on-site diagnostic kits have emerged as a promising tool for quickly identifying viral diseases right in the field. Traditional laboratory-based techniques such as ELISA and PCR are highly accurate but require specialized equipment and time-consuming procedures. In contrast, on-site kits based on techniques like lateral flow assays, loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA), and CRISPR offer faster results with similar sensitivity and specificity. These methods also minimize sample handling and can be used effectively even in lower-resource settings like agricultural farms. This chapter delves into how the latest on-site diagnostic tools, such as LAMP and CRISPR-based kits, work in detecting plant viruses, reviews real-world uses on farms, current limitations, and promising innovations pushing field detection forward.