Current Status of Tomato Chlorosis Virus and Whiteflies in Potato Crops of São Paulo State and Virus–Vector–Host Interactions

ABSTRACT Potato is a vital food source worldwide, but its production is frequently threatened by viral diseases. Tomato chlorosis virus (ToCV) primarily affects solanaceous crops, especially tomatoes. Although ToCV has been reported in potatoes, its relevance in this crop remains understudied in Brazil. This study evaluated the incidence of ToCV in major potato‐producing regions of São Paulo state and identified the predominant whitefly species. Transmission efficiency of ToCV by Bemisia tabaci MEAM1 and MED, vertical transmission via tubers, and the latent and incubation periods in potato plants were also investigated. Field surveys (2022–2024) showed a low ToCV incidence in potato crops. MEAM1 was the predominant whitefly species, whereas MED was detected at a single location. MED transmitted ToCV to potato plants of cv. Agata with higher efficiency (36.6%) than MEAM1 (10%), but no significant difference was observed for plants of cv. Asterix. Vertical transmission rates via tubers were high, reaching 76.7% for cv. Agata and 88.1% for cv. Asterix. The mean latent period was 8 days, with symptom expression approximately 35 days post‐inoculation. These findings suggest that ToCV is currently not widely distributed in potato crops in São Paulo state. However, the high vertical transmission rates and the demonstrated transmissibility by both MEAM1 and MED highlight the potential risks for future spread. Continued monitoring of potato fields and whitefly populations is crucial to mitigate the potential risk posed by ToCV in the region.