Recent rainfall and warm temperatures in some parts of the South West may lead to conditions conducive for aphids to spread soybean dwarf virus (SbDV), which has been identified as a key contributor to sub clover red leaf syndrome.
The symptoms to look out for included red leaves, stunted plants and even premature plant death.
Department of Primary Industry and Regional Development (DPIRD) science officer Paul Sanford said SbDV was not a seed-borne virus but was spread by aphids.
"If growers can control the aphids there is a good chance they can manage the syndrome," Mr Sanford said.
"Autumn control options include spraying for aphids using an anti-feeding insecticide at two and six weeks after sub clover seedlings emerge.
"Oats can also be sown as a barrier around pasture paddocks to disperse aphids and slow early spread into pasture from outside sources."
DPIRD and The University of Western Australia (UWA) want to test plants with symptoms as part of a broader work to better understand this syndrome, which can severely stunt pasture growth.
Farmers who suspect red leaf syndrome in their subterranean clover can access free testing by the DPIRD Diagnostic Laboratory.
This work is being done in collaboration with the Grains Research and Development Corporation project which is examining virus threats to the grain pulse industry.
More detailed information, including how to identify and manage the impacts of subterranean clover red leaf syndrome, is available from agric.wa.gov.au.
Growers wishing to arrange free testing, can contact Mr Sanford at firstname.lastname@example.org or Kevin Foster of UWA at email@example.com
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