Don’t let summer growth provide disease green bridge
5 April 2017
Grain producers are being urged to remove green self-sown crops ahead of this year's growing season to reduce the impact of crop diseases.
Speaking at this month's "Hey Hay!" workshops across the Wimmera, Agriculture Victoria plant pathologist Luise Sigel told growers that volunteer crops in summer provide a 'green bridge', enabling soil-borne diseases and rusts to survive and build up.
Ms Sigel said that this season's crop would potentially be faced with an epidemic of rust due to high levels of inoculum arising from green crops and weeds in the lead up to sowing.
"Ideally, remove volunteers (self-sown crop plants) well before sowing to break the green bridge, ensuring at least one month of no green host plants," she said.
"Rusts need living plants to survive. We recommend keeping paddocks free from living plants at this time of year to ensure there is a break in the disease cycle.
This includes monitoring fence lines, silos and sheds for rust-susceptible weeds and volunteers. We consider rust a 'social disease', so it is important that everyone is on board with green bridge management," Ms Sigel said.
While volunteer crops can provide valuable livestock feed, Ms Sigel warned that grazing was not fully effective in breaking the life cycle of rusts and soil-borne diseases.
"Levels of soil-borne diseases may increase with the presence of cereal volunteers and weeds. For example, root lesion nematode has a wide host range including weeds such as barley grass."
Ms Sigel said green-bridge removal also helped manage the spread of viruses in crops.
"It's an important part of a disease management strategy," she said.
"Insect pressure, nutrient removal and soil moisture depletion were other reasons to remove the green-bridge", said Ms Sigel.
The "Hey Hay!" workshops were funded through the Drought Program of Agriculture Victoria.
For more information on crop diseases this season, contact Luise Sigel on (03) 5362 2111.
Categorised under: Agriculture