AS most of the state’s crops experience good moisture levels, SARDI pulse pathologist Jenny Davidson, Waite campus, said there was one key piece of advice.
“If you can get onto your paddocks, spray,” she said.
Speaking at the recent Hart Field Day on the topic of pulse disease management, Dr Davidson said the high moisture this year meant many of the SA’s pulse crops could be impacted by a range of fungal diseases that could be managed by spraying fungicides at the right time.
Colleague and co-presenter Rohan Kimber said one example was faba beans, which have thick canopies on wet soil.
He advised growers to spray for chocolate spot and ascochyta in certain areas, before the canopy closed.
“The wet soil will drive humid conditions in bulky crops,” he said.
Dr Davidson also warned lentil growers to reconsider their rotations amid concerns about ascochyta resistance in some key varieties.
With high lentil prices at sowing this year, she said the crop was popular, particularly the PBA Hurricane XT variety, which makes up about half the lentil crop grown on the Yorke Peninsula.
“We’ve got a lot of Hurricane planted next door to PBA Hurricane XT stubble, or even two years of PBA Hurricane XT,” she said.
“Under that kind of pressure, we’re not sure how long will be able to keep ascochyta resistance.”
Dr Davidson said PBA Hurricane XT and another popular lentil variety, PBA Jumbo 2, had resistance to ascochyta.
They had different enough pedigrees, and presumably different resistance genes, so a rotation of the two could stave off resistance for a little longer, she said.
She said there had also been changes to the recommendations for blackspot in field peas.
The previous guidelines were developed 10 years ago, and said to spray twice if a crop was likely to yield at least two tonnes a hectare.
With crops rising in value and fungicide costs decreasing, the guideline has been revised to spraying crops likely to yield at least 1.5t/ha.
“Spraying can bring a 15 per cent yield gain, which provides a profit more than double the cost of fungicide,” Dr Davidson said.
She recommended growers sign up to the free Blackspot Manager Service, which forecasts the timing of the release of blackspot spores each year, which could indicate best sowing times or fungicide use.
There were other diseases to look out for in field peas, including powdery mildew.
“It (powdery mildew) moves extremely fast, and we suggest to get the fungicide spray out with insecticides or earlier,” Dr Davidson said.
Bacterial blight is another concern, which can be brought on by frost.
“If you do have it, there is nothing you can do except shut the gate and stay out, as it’s very infectious,” she said.
Botrytis grey mould is also a risk for lentils in a wet season.
Dr Davidson recommended fortnightly sprays on PBA Hurricane XT lentils, given the amount of rain and, while PBA Jumbo 2 has good resistance, with the extra pressure of this season, it should be sprayed monthly.