Western Victorian canola growers are being urged to look out for green peach aphids in their canola and pulse crops with conditions favourable for Turnip yellows virus this year.
Agriculture Victoria research scientist Piotr Trebicki issued the warning after observing green peach aphids and Turnip yellows virus (previously known as Beet western yellows virus) in paddocks south of Horsham.
“The volunteer plants and weeds that sprung up following late summer and early autumn rain provided good conditions for aphid populations to increase,” he said.
The virus, which is spread by the green peach aphid, can cause significant yield losses in canola and pulse crops, particularly when infection occurs at an early growth stage.
“If transmitted to canola or other crop species at an early growth stage it can cause total crop losses,” Dr Trebicki said.
“Infection at a later growth stage has a less severe impact on canola and most pulses, however chickpeas are very vulnerable to virus infection at any growth stage.”
Typical symptoms of Turnip yellows virus include stunted plant growth and leaves showing a yellow or purple discolouration.
A recent virus survey conducted by Agriculture Victoria showed an increase in Turnip yellows virus, particularly in paddocks where summer weeds, self-sown canola and spring sown canola were growing.
Dr Trebicki said the risk of infection increased when crops were sown in, or adjacent to, paddocks that hosted large aphid populations or where the virus was already present.
“As conditions this season are so far conducive to virus spread, growers are urged to monitor their crops, control weeds and volunteer canola or pulses and to treat plants with a registered insecticide if necessary.”
See our page on Turnip yellows virus