SCLEROTINIA has adversely affected the majority of canola crops in the Cowra area, said Elders production agronomist, Peter Watt.
“The combination of a wet year, fewer sunlight hours, higher humidity, and water-logged soils has created the perfect conditions for widespread disease by this stem-rotting fungus that affects the plants between flowering and seed-filling,” he said.
“Growers who applied fungicide at 20 per cent flowering have derived some benefit in having less of their crop affected.
“However, due to water-logging, many farmers simply couldn’t get on to their country and weather conditions minimised the use of aerial spraying.”
Mr Watt said in spite of the heights of the Lachlan River, very little area of canola had been lost to flooding.
What started as a really promising year has become a disappointment for many growers.
- Rohan Brill.
“Water-logged soils created anaerobic conditions reducing the plant’s metabolic processes resulting in impaired nutrition and making it more vulnerable to infection from the fungus.”
According to Rohan Brill, canola agronomist with the NSW Department of Primary Industries, Wagga Wagga, windrowing will probably start this week as conditions have finally dried out so the first stage of harvest can commence.
“The best crops I’ve seen are those where the right phenology came together with a minimum of damage from sclerotinia or black leg, both which are high rainfall diseases.
“As in other canola growing regions, this has been an exceptional year for rain and associated fungal problems.
“What started as a really promising year has become a disappointment for many growers.”
In the Riverina and Central West the majority of canola crops this year are open-pollinated, non-hybrid, triazine-tolerant varieties, the seeds of which growers can retain year-on-year.
“The downside is diseases may be carried into each successive growing season, exacerbating the continuous spread of sclerotinia which builds up in paddocks from where the fruiting bodies emit their spores,” Mr Watt said.
“Internal paddock hygiene may be excellent but sclerotinia is endemic in all canola growing areas now.
“That’s why we encourage changing varieties periodically to break disease-cycle.”
Different conditions, different production
CANOLA crops are looking to yield above average around the north, with producers in the Liverpool Plains gearing up for harvest, says Local Land Services, Senior Land Officer, Dale Kirby, Gunnedah.
While some crops had been hit with sclerotinia, Mr Kirby said disease and insect pressure was handled well by producers throughout the season.
“They won’t have a big effect on yields,” he said.
Growers who have opted to windrow in the Plains have started doing so in preparation for harvest.
Mr Kirby said the season needed a dry, warm finish over harvest to maintain good quality.
Quirindi Grain Trading’s John Webster, said there was more canola growing than in previous years and due to the wet season a lot had lodged because plants’ root systems had never “got going”.
“But there’s some good crops about,” he said.
Wellington-based agronomist, Michael White, said there was a mix of excellent crops and disasters in the valley.
“There’s no real pattern, but crops lying in waterlogged or boggy conditions have attracted Sclerotinia and black leg through stressing,” he said.
Nonetheless Mr White predicts to up a two-tonne per hectare yield with a 1.6t/ha yield this year, providing there is a positive season finish.
NSWDPI’s pulses and oilseeds technical specialist, Don McCaffery said there had been an early finish to flowering of up to a fortnight, “which possibly was due to the lack of energy in plants’ low solar radiation throughout the growing season”.
An early finish like this was more often seen in a hot, dry spring where the topmost pods don’t fill.
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