Ocurrence of potato virus Y on potato crops in São Paulo state and effects of virus infection on tuber production and plant emergence

Potato is one of the world's most important food crops, and its production is susceptible to losses caused by viruses such as potato virus Y (PVY), one of the most significant phytopathogens affecting potato-growing regions globally. This study aimed to: determine the incidence of PVY in potato cultivation areas in the state of São Paulo over the years 2023 and 2024; identify the predominant PVY strain in the analyzed areas; evaluate the impact of PVY infection on potato plants of the Agata and Asterix cultivars; and assess the effect of PVY on plant emergence. Based on biological and molecular analyses, the strain used in this study in the biological assays was identified as PVY ^NTN . The field survey conducted in 2023 and 2024 revealed an average PVY incidence of 15.3% and 13.6%, respectively. The predominant strain in these areas was PVY ^NTN . The biological assays showed that infection by this strain caused a marked reduction in tuber yield and plant emergence in both Agata and Asterix cultivars. Tuber production was reduced by 34.4–68.1% in Agata and 42.8–53.7% in Asterix. Plant emergence from tubers produced by PVY-infected plants also declined significantly. On average across two experiments, plant emergence from PVY-infected tubers was significantly reduced, from 77.5–26.3% in Agata and from 76.7–37.1% in Asterix. These findings highlight the negative impact of PVY on potato production, emphasizing the need for management strategies to control virus spread, particularly in regions where PVY incidence is high.