Quantification of mineral oil accumulation and movement in potato plants and its significance in potato virus Y management

Abstract

The information generated in this study on the pattern of accumulation and movement of mineral oil in greenhouse- and field-grown potato plants shows that, as the oil does not move from leaflet to leaflet, frequent mineral oil sprays from crop emergence to harvest are required to prevent PVY infection in newly emerged leaflets and seasonal spread of PVY. The frequency of sprays may be kept higher from early to mid-stage, when plant growth is faster, and lower close to plant maturity.

Control of potato virus Y (PVY) in seed potatoes by oil spraying, straw mulching and intercropping

“…Weekly applications of mineral oil from the time of crop emergence is a common but labour‐intensive virus management measure in seed potatoes and is known to reduce PVY transmission by roughly half, albeit with important variation among environmental conditions (Boiteau & Singh, ; Martin‐Lopez et al ., ; Boiteau et al ., ; Hansen & Nielsen, ; Fageria et al ., ; Kirchner et al ., ; Steinger et al ., ). In the present study, mineral oil applications reduced PVY incidence by an average of 43%, with considerable year‐to‐year variation, which is consistent with the literature.…”

“…The increase in leaf area is the highest after plant emergence and declines until senescence (Shands et al ., ). As new leaves emerging after oil sprays are susceptible to PVY infection (Fageria et al ., ), potato crops may face a relatively higher risk of infection during the early stages of crop development compared to later in the season, assuming the common practice of constant (weekly) applications of mineral oil. Consistent with this reasoning, a lower efficacy (27–39%) of oil spraying was found in the years 2011 and 2013, when aphid activity was high early in the season, and a higher efficacy (67%) in the year 2014, when aphid vectors appeared relatively late in the season.…”

“…Mineral oil can reduce the acquisition and retention of PVY by aphids (Wróbel, ; Boquel et al ., ). Nevertheless, the efficacy of mineral oil in controlling the spread of PVY varies widely, from 18% to 89% (with an average of 49%) depending on the study (Boiteau & Singh, ; Martin‐Lopez et al ., ; Boiteau et al ., ; Hansen & Nielsen, ; Fageria et al ., ; Kirchner et al ., ; Mackenzie et al ., ; Steinger et al ., ). There is a profound need to increase the efficacy and stability of mineral oil treatments, e.g.…”