South Perth, Western Australia
February 9, 2004
Last year's
improved conditions have resulted in seven times as many
positive lupin anthracnose seed tests at the
Department of Agriculture
of Western Australia.
Department
plant pathologist Geoff Thomas said anthracnose was more
prevalent in lupin crops than in previous seasons.
"Several crops
suffered significant yield damage, however in general, disease
levels were not high enough to cause widespread yield loss but
will have resulted in infected seed being harvested," Mr Thomas
said.
Results from the Anthracnose seed infection tests
submitted to AgWest Plant Laboratories (APL) support this
observation. Approximately 38 per cent of all samples tested
from the 2003 crops were positive.
Comparatively, approximately five percent of
tests from the previous two seasons have been positive. Positive
samples have been received from the Northam, Moora, Three
Springs and Geraldton regions.
Mr Thomas said the increased number of positive
seed tests indicates many seed lots might contain higher levels
of infected seed in the coming season.
Mr Thomas said seed infection was the primary
method of transfer of anthracnose and could result in
significant yield loss due to the early build up of infection in
crops. Another season like 2003, combined with a higher level of
infected plants in crops could generate significant yield
losses, particularly in high and medium rainfall areas.
"Infected seed poses a threat to all varieties
however the risks are greatest in susceptible or moderately
susceptible varieties and least in resistant varieties such as
Wonga and Tanjil," he said.
"Anthracnose control relies on variety selection,
the use of clean seed and thiram seed dressing and reducing or
avoiding other inoculum sources, such as blue lupins."
A quantitative
DNA based 10,000 seed test is available commercially through
APL.
Seed
Submission forms and instructions are available by faxing APL on
9474 2658. Further information on the importance of seed borne
infection and critical seed infection thresholds is provided
with seed test results or via the Department website at
www.agric.wa.gov.au |