IN SPITE of a dry year not favourable for the spread of many fungal diseases in grain crops, plant pathologists have warned there have still been issues with disease this year.
Loose smut in barley has been particularly notable this year.
The disease can be present on infected seed and show no symptoms.
When infected seed germinates, the fungus becomes active and grows slowly in the growing point of the plant before then becoming apparently as the fungus forms a compact spore mass around the plant head.
Agriculture Victoria plant pathologist Mark McLean said the breakdown in resistance was particularly notable in some barley varieties.
“We’ve had quite a rate of infection in untreated Spartacus,” Dr McLean said.
However, the good news for growers is that with seed treatments the damage is limited.
“You would only expect a couple of percent of yield damage with the correct seed treatment, but if seed was left untreated there could be quite a dramatic yield loss.”
Official Western Australian Department of Agriculture research released in July said seed treatment efficacy was good enough that farmers could afford to use infected seed provided it was treated, even considering the fact that some export markets, such as Pakistan have zero tolerance for loose-smut infested grain.
Meanwhile, Dr McLean said scrutiny of oat crops this year had revealed some little known diseases.
“They all present fairly similarly, but we have been seeing barley yellow dwarf virus, red leather leaf disease and bacterial blight in various oat crops.”
He said there was little in the way of treatment for the diseases at present.
“You obviously can’t treat a bacterial blight or a virus with fungicide, but even with red leather leaf, which is a fungal disease, there is no product registered for use.”
Dr McLean said the dry finish to the season meant the diseases would be unlikely to cause significant damage this year but added it would be something to monitor into the future.