[ASC-media] NO BLACK SPOTS SO FAR: Crop Doctor
brendon at iinet.net.au
Wed Jul 30 03:03:16 CEST 2008
NO BLACK SPOTS SO FAR 30.7.08
So far, the 2008 growing season has not seen significant blackspot in field
peas in WA, which is good news for growers in Esperance and the Northern
Agricultural Region, where the disease, in its severe form, can destroy an
Windblown ascospores, produced by the fungus on the previous seasons
infected pea stubble, are the key agent causing blackspot infection of field
Resistant varieties are not available and fungicide control is not economic,
hence management has depended on agronomic or cultural practices.
The principal strategy has therefore been to delay sowing peas until the end
of the sowing window to avoid most of the ascospores released from pea
A predictive model, Blackspot Manager, has been developed by researchers
from the Department of Agriculture and Food WA (DAFWA), with Grains Research
and Development Corporation support.
Blackspot Manager uses pre-season temperature and rainfall to forecast onset
and progression of air-borne ascospores released from infected field pea
stubble during a growing season.
Modelling coordinator, Dr Moin Salam of DAFWA, says the model, when tested
at 14 sites in WA and seven in SA last year, showed the predicted onset of
ascospore release agreed with observations of actual disease levels.
Dr Salam says Blackspot Manager also predicts incidence and frequency of
ascospore release during the growing season, based on weather to-date and
then projecting forward, given a range of possible seasonal scenarios.
Validation of the model is continuing in both states in 2008. Predictions
for ascospore release are available from www.agric.wa.au/cropdiseases
The information can be use to determine sowing dates of low disease risk.
The Crop Doctor is GRDC Managing Director, Peter Reading, Tel 02 6166 4500
Further Information: Dr Moin Salam, Tel 08 9368 3333
GRDC REF: CDJuly084.doc/DAW00106/Rainbow280708
Brendon Cant & Associates
Public Relations & Marketing
4 Gugeri St
Claremont WA 6010
Tel 08 9384 1122
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