Australia
May 15, 2009
Source:
Grains Research and Development
Corporation (GRDC)
Growers of canola are being
advised to manage blackleg risk in this year’s crop by adopting
a strategic sowing program.
To minimise the risk of blackleg, growers are urged to separate
this year’s canola crop from last year’s canola stubble by a
distance of at least 500 metres.
According to Trent Potter, senior research scientist at the
South Australian Research and Development Institute (SARDI), it
is also recommend that growers avoid planting a crop of canola
within 500 metres of stubble of the same variety sown up to two
seasons prior.
“Fungal spores from a stubble are more likely to infect the same
variety more severely the following season,” Mr Potter said.
“Growing the same canola cultivar for the third year or more
enhances the risk of blackleg infection.”
And while the risk of blackleg is greater in higher rainfall
areas (those with a growing season rainfall of more than 330
millimetres), Mr Potter encourages all growers to take steps to
reduce the incidence of fungal blackleg.
To assist growers with blackleg management, a fact sheet has
been developed based on surveys, trials and research funded by
the Grains Research and Development Corporation (GRDC) and the
Australian Oilseeds Federation (AOF).
Surveys and data for the fact sheet were provided by the Lower
Eyre Agricultural Development Association farming system group,
MacKillop Farm Management Group, SARDI and Marcroft Grains
Pathology.
In addition to sowing recommendations, the fact sheet provides
variety advice. Growers are advised to choose a canola variety
with good blackleg resistance and to ensure that canola seed is
treated with a fungicide as an insurance agent against blackleg.
Growers should also monitor for blackleg within the 2009 crop.
Mr Potter said canola remained an important component in
southern cropping rotations. Its value in weed management and as
a cereal disease break crop continues to be recognised, and
wheat yields are on average 20% higher after canola than after
wheat.
Timing of sowing would again be a critical factor for growers
this season, according to Mr Potter: “If they can get the crop
in early enough, they have the potential to make good money from
canola.
“However, that potential is reduced with any delay in sowing.
Yield is likely to drop 5% per week in South Australia and
Victoria, and 10% per week in southern and central NSW. Oil
content will fall 0.5 to 0.8 percentage points per week with
delayed sowing.”
Mr Potter said the optimum time for sowing canola differed from
one region to another. For example, growers in low rainfall
areas, such as the Mallee, have a narrower window for sowing,
one which generally closes after the third week of May. In the
low rainfall areas of southern and central NSW, it closes even
earlier, after the first week of May.
In higher rainfall areas, such as the South-East of SA,
reasonable yields can be achieved from crops sown as late as
early July.
Growers wanting to know more about how they can reduce the
incidence of blackleg this season can obtain the fact sheet,
Managing Your Risk of Blackleg in Canola, via
www.grdc.com.au/managingblacklegreport |
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