South African potato production is being severely reduced by an outbreak of leaf-roll virus.
Potatoes South Africa said infected seed potatoes cannot be used for planting and this has significantly increased production costs -- from between 35,000 and 44,500 rand (US$5,477 and US$6,964) a hectare three years ago to between 46,000 and 54,000 (US$7,198 and US$8,450) this year.
The virus, carried by aphids, can spread more than 900 miles.
Potatoes South Africa Western Cape manager told Farmers' Weekly that the virus has also caused a shortage of seed potatoes.
He said producers should only buy plant material from agents accredited by the National Seed Potato Traders Forum. This material is tested regularly to show its disease-free status.
"Producers should only use healthy plant material to prevent diseases from spreading to their land," he said.