AgroPages-Viral yellows spreads on canola in South Australia-Agricultural news

South Australian farmers affected by beet western yellows say their crops are facing an uncertain future. It's estimated around 7000 hectares of canola in the state could be affected; the worst case ever seen in Australia.

The virus is being transmitted by green peach aphids, which have thrived in recent warm conditions. Farmers and agronomists say they still don't know how to deal with the virus. Farmers face huge yield losses. Tests have indicated a 90% infection rate in some crops. Farmers said "the crop is just struggling to even stay alive, let alone put on any yield. We've never dealt with this before."

Agronomists and scientists are just as baffled. The South Australian Research and Development Institute (SARDI) says tests have confirmed very high rates of infection particularly in the lower north. But scientists are still investigating why this virus has spread so far and whether it may start affecting pulse crops.

SARDI's Greg Baker says spraying crops now would be a waste of time, because the virus-transmitting aphids are inactive. But, as the weather heats up, farmers should still monitor for early signs of aphid activity and use that as alert for crops being at risk and requiring preventative sprays.

News of the virus is spreading overseas and influencing the global canola price. Australia is the world's 2nd largest producer of canola, with South Australia a major exporter to Europe.