THE constant threat to the wool industry from the dangerous weed noogoora burr was highlighted recently, when the samples of the plant were found in horse feed in Geraldton.
WA Inspection Service officer Greg Croker said analysis certificates of the feed showed no evidence of contamination.
"The feed supplier had done the right thing by ensuring the consignment was examined for contamination," Mr Croker said.
Mr Croker said the risk of further noogoora burr contamination in the consignment was minimal, however he said the incident was a good reminder of the need for both feed suppliers and purchasers to remain vigilant.
Agriculture WA protection officer Fred Hearn said noogoora burr was a dangerous weed that had the potential to devastate the State's valuable wool industry.
"The burrs can be very difficult to remove from wool, which adds a cost at the processing stage, which devalues contaminated wool by about 15 cents per kilogram," Mr Hearn said.
"It is also poisonous to stock at the seedling stage and the dry burrs may cause discomfort and injury, particularly to sheep. The weed can grow so densely that cattle and sheep cannot get access to watering places."
Noogoora burr stems grow normally up to 2.5 metres in height but occasionally reach four metres.
Isolated plants have a branched stem, however plants growing in a clump are usually single stemmed.
The stems lack spines, but have a fine bristly covering, which are often arranged in a zig-zag manner and usually carry purplish blotches or streaks in young plants.
The leaves are similar in appearance to a grapevine leaf, but have a rough texture.
Any sightings of noogoora burr should be reported to the local Agriculture WA office.