An emergency approval has been granted for a mineral oil product to treat seed potato crops, offering growers a tool against non-persistent aphid-vectored viruses.
Crop protection firm Certis Belchim has had its mineral oil Olie-H approved following an application by potato sector bodies, including Seed Potato Organisation, GB Potatoes and SAC Consulting.
Applying mineral oils as adjuvants is a way growers can manage potato virus Y (PVY), which work by coating the crop’s leaves with a thin film which then disrupts the acquisition and transmission of virus by the aphid’s stylet.
Non-persistently transmitted potyviruses, sometimes called mosaic viruses, have been the most problematic of viral diseases affecting British potato production for years and currently, the dominant species is PVY.
Caroline Williams, UK potato crop manager at Certis Belchim, said that until now mineral oil products have only been permitted from emergence up to tuber initiation in seed potato crops.
This led to Horticulture Crop Protection, Seed Potato Organisation, GB Potatoes, SAC Consulting and VCS Potatoes applying for an emergency authorisation for the company’s paraffin oil product Olie-H for use from tuber initiation onwards.
“The application has been successful and seed growers will benefit from the proven efficacy of oils for the entire growing season in 2024, helping suppress non-persistent virus levels in seed stocks,” said Ms Williams.
“We recommend that Olie-H is always applied to a dry leaf and growers avoid applying it in the heat of the day. It’s also best used as part of a virus control programme containing translaminar insecticides like Teppeki and InSyst.”
PVY is most damaging in ware crops grown from infected seed, depending on the variety affected plants can lack vigour, producing smaller and sometimes misshapen or cracked tubers.
When aphids probe the leaves of plants infected with PVY, they can pick up the virus and transmit the disease very quickly – within minutes or even seconds of probing an uninfected plant.
This in contrast to persistent viruses like potato leaf roll virus, which take much longer for an aphid to acquire and become infectious, so aphids that colonise potato crops – such as the peach-potato aphid – are key to its transmission.
Non potato colonising aphids like the grain aphid and willow-carrot aphid, as well as colonising aphids, can spread PVY quickly as they move through potato crops.
This wider range of vectors and speed of transmission make it very difficult to manage, and key vector species have developed resistance to pyrethroid insecticides, so it has only become trickier in recent years.
VCS Potatoes agronomist Graham Tomalin, who oversees seed potato crops across East Anglia where PVY is a significant threat, welcomed the news of the successful application.
He said: “It’s been an excellent team effort to gather all the evidence on the risk posed by PVY in British seed production and make a case for the emergency approval.
“Olie-H is a useful addition to integrated pest management (IPM) strategies, with a broad range of measures key to lowering virus levels and maintaining good seed potato health.”
