Western Australia
May 3, 2007
This growing season the risk of
reduced crop yields due to diseases generated over summer from
the green bridge will be restricted to the far south and
south-eastern grainbelt, according to an innovative WA
‘greenness’ forecasting model.
 Centre
for Legumes in Mediterranean Agriculture (CLIMA) researcher,
Tim Maling, has developed a new predictive framework to forecast
bean yellow mosaic virus (BYMV) and aphids in lupin crops, which
will mean greater productivity and lower costs for growers.
“Usually about 700,000 hectares of narrow leaf lupin are sown in
the Western Australian grainbelt, with potential for more than a
million hectares,” Mr Maling said.
“However, aphids and the viruses they transmit can dramatically
slash lupin yields, especially when they arrive early in the
season,” he said.
Mr Maling said his ‘greenness’ model utilised meteorological
data, before and during the growing season, to estimate pasture
capacity for aphid populations and determined a greenness level
using daily temperature, rainfall and evaporation data.
Aphid-borne, non-persistent BYMV is not seed transmitted in
lupins, so crop infection relies on BYMV-infected pasture being
adjacent to the lupin paddock and an aphid population sufficient
to start spreading the infection early.
The modeling framework, developed through an Australian Research
Council (ARC) industry linkage project and supported by the
Department of Agriculture and Food WA (DAFWA), can automatically
retrieve data, facilitating higher resolution and quicker
forecasting.
“This will greatly improve researcher and grower understanding
of what drives virus epidemics and aphid outbreaks in WA in any
season,” Mr Maling said.
“This year, high Western Australian greenness levels in
mid-April are mainly restricted to the southern and
south-eastern grainbelt, although a small patch of greenness can
be seen in the north-east.
“These areas are where green bridge mediated diseases will be
most prevalent and growers should regularly monitor any green
bridge near their crops to assess infection risk and the need
for management strategies,” he said.
The model framework has also produced maps for
DAFWA’s cucumber mosaic
virus (CMV) website, which provides an annual forecast for CMV
and aphid risk in WA lupins based on different sowing dates and
seed infection levels.
Mr Maling has automated a CMV model originally developed by
CLIMA researcher, Dr Debbie Thackray with funding from the
Grains Research and Development Corporation, so that it picks up
climate data for the season to date, combines it with archived
data for the rest of the year and delivers maps of CMV risk for
worst, best and medium case scenarios.
“The good news for the 2007 growing season is that throughout
the grainbelt, the CMV model shows low risk of early aphid
arrival and subsequent lupin yield losses from crops sown with
low seed infection levels of 0.2% or 0.5%,” Mr Maling said.
Mr Maling’s project supervisor, DAFWA Plant Virologist Dr Roger
Jones, encouraged growers to minimize the risk of infection by
having representative samples of lupin seed tested at AGWEST
Plant Laboratories at South Perth.
“Most growers are likely to plant seed with less than 0.5 per
cent infection, but in some areas they need to be especially
vigilant, particularly the south-coast shires, where the risk of
yield loss is high, with a greater than 0.5 per cent seed
infection rate,” he said.
Management options are described on the website
www.agric.wa.gov.au/cropdiseases |
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