Brendon Cant brendon at iinet.net.au
Wed May 17 11:26:11 EST 2006

Crop Doctor



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WA grain growers may face a new weed menace that could seriously impact
pastures, legumes and oilseed crops. 


The threat is a parasitic weed, red dodder, which has been found in 27,
mostly non-cropping, locations from Monkey Mia to Mandurah and Eucla to


This dodder species was discovered in a Geraldton grower’s canola crop in


While the weed is still hard to find, such wide dispersal suggests it could
become more widespread.


Grains Research and Development Corporation (GRDC) supported Department of
Agriculture and Food senior researcher, Dr Abul Hashem said dodder reduced
pods or burrs per plant by an average of 20 per cent in lentil, 50 per cent
in faba bean, 60 per cent in lupin, 75 per cent in chickpea and up to 100
per cent in subterranean clover.


And yields aren’t the only victim of this potentially damaging weed. It
could also cause grain to be rejected at the receival bin, because some
export markets have zero tolerance to dodder.


Dodder seeds have high dormancy, can germinate over a range of temperatures
and are mildly toxic to livestock.


In the initial days of its life cycle, dodder is fully dependent on its
roots for mineral and water uptake and is therefore extremely vulnerable to
external stresses.


Dr Hashem said a dodder plant must contact a suitable host plant within
eight days and delaying crop sowing could reduce emerged dodder plant


Pre-sowing herbicides such as diuron, propyzamide, metribuzin, imazethapyr
and trifluralin controlled 91 to 100 per cent of dodder plants.
Post-emergent herbicides, such as atrazine, controlled 100 per cent, while
metribuzin and picolinafen were 83 per cent effective.


The GRDC supported project established how to break dodder seed dormancy,
how it parasitises broadleaf crops, how it affects pod production and how it
is controlled with herbicides.


It will be important to monitor this potential pest plant closely to gain a
better understanding of the risk it poses.



The Crop Doctor is GRDC Managing Director, Peter Reading, Tel 02 6272 5525

Further Information: Dr Abul Hashem, Tel 08 9690 2000

GRDC REF: cdapril063.doc/DAW00028/Sandow


Brendon Cant & Associates
Public Relations & Marketing 
Suite 5
4 Gugeri St
Claremont WA 6010
Tel 08 9384 1122

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