Mineral oil interferes with potato virus Y in aphid stylets

Mineral oils have been used for many decades to control the transmission of plant viruses and their ensuing epidemics. Although it is not clearly defined, the mode of action of these oils has been extensively studied, and effects on the feeding behaviour and orientation of the vector or the transmission of the virus by its vector have often been put forward as possible explanations. This study examines the effect of mineral oil on the interaction between potato virus Y (PVY) and its vector, the green peach aphid Myzus persicae, with particular focus on the transmission organ. A lipophilic staining technique was used to visualize the oil inside the insect's stylets for the first time. Virus binding and localization were also examined in aphid stylets following PVY acquisition. The results indicate that the presence of mineral oil on leaves reduces the likelihood of acquiring the virus. This study verified that this reduced acquisition could be accompanied by a reduction in viral load, as measured by reverse transcription-quantitative PCR on the stylets. The effect of the oil on virus retention inside the stylets was also measured. The mechanism by which the oil impacts virus acquisition seems to take place in the very early stages of acquisition, well before the virus attaches to the stylets.