Mineral Oil Inhibits Movement of Potato Virus Y in Potato Plants in an Age-Dependent Manner

Potato Virus Y (PVY) is one of the most devastating pathogens threatening potato production worldwide. It is a RNA virus that is disseminated by aphids in a non-persistent manner. Regular application of mineral oil on potato fields is known to reduce the number of PVY-positive tubers in post-harvest testing. The mechanism of this phenomenon is not well understood, but it is hypothesized to influence the virus-vector-plant relationships. Here, we present data from greenhouse and field trials that shed light on the effect of mineral oil on local and systemic accumulation of PVYO in susceptible Shepody and Russet Burbank. The data suggests that mineral oil did not influence PVYO levels in mechanically-inoculated leaves nor tubers of plants with a secondary infection. However, a reduction in systemic PVYO levels was observed in mineral oil-treated older plants but not in younger plants, suggesting that mineral oil inhibits PVYO movement in an age-dependent manner.