Dear colleagues,
I am researching long -term sustainability in broadcare dryland farming systems in
southern Australia. A major part of this work involves conducting a long-term trial
comparing organic, biodynamic, integrated and conventional farming systems. The trial,
now in its eighth year, is getting pretty interesting, and will deliver a lot of useful
information over the next four year rotation cycle, funding permitting.
A major problem identified from this trial, and very much on organic farms, is weed
control. While all the best management strategies can be used, including rotations,
sheep grazing, hay cutting, delayed seeding, increased seeding rates etc, it does not
always work. Their are also some perennial weeds which do not respond to these
practices, and importantly, the farmers should not go broke through being committed to
organic practices.
In our case, the main problem weed is soursob (Oxalis pes-caprae), a bulbous perinnial,
which abides by the above criteria. It is readily controlled with sulphonolurea
herbicides, but that is not an option here.
I am in the process of trying to convince the organic certifying organisations that we
need to look at some of the microbial herbicides for instances such as this. The one I
have in mind is bialaphos, sometimes called bilanaphos or herbi-ace. It is made and
marketed in Japan, and I believe also sold in the UK (under the name Challenge). It is
produced by fermentation from the Streptomyces hygroscopicus bacterium, and produces
broad spectrum herbicidal effects, being slightly faster acting than Glyphosate, but not
as readily translocated.
I would be very interested to hear where around the globe the product is used, its
price, effectiveness, and whether it or any other herbicides are permitted within the
countries certified organic standards.
Such information would be greatly appreciated.
Chris Penfold
Uni. of Adelaide
Roseworthy Campus
Roseworthy, South Australia 5371.