Maxine Lyndall-Murphy, WormBuster Lab, Brisbane, (Maxine.Lyndal-Murphy@deedi.qld.gov.au):
We’re not out of the woods yet…temperatures may be falling but the maxima in most regions are still within Barber’s Pole comfort zone of 20°C+ - the cool nights will just slow this worm down a bit.
Some research work at Goondiwindi a number of years ago followed worm egg counts in mobs of sheep over a three year period to identify the temperatures that inhibited hatching of Barber’s Pole eggs in dung. It was concluded that when the diurnal temperature range was wide as it is in winter, the important temperature to watch was the maximum…so in the next few months, unless the daytime maxima fall consistently below 18°C (typically around Stanthorpe), reâ€infestations with Barber’s Pole will still be possible - especially if it rains.
We are currently setting up resistance tests across the region and are surprised by the heavy worm burdens in young sheep so late in the year - due to the wet autumn.
For instance, districts with counts over 2000epg include Balonne, Barcaldine, Clifton, Ilfracombe, Millmerran, Paroo, Pittsworth, Waggamba, Warwick and Winton.
If we get a mild wettish winter as some predict, big worm challenges across almost all of the State are certain.
The most neglected drench: The quarantine drench.
If you bring sheep onto your property, drench them. You can’t know the resistance level of worms carried by imported sheep so use the recommended Zolvix plus 3 unrelated drench actives. If sheep were drenched at the property of origin then ‘top up’ the drenches dosed to the recommended strategy.
It’s expensive and time consuming, but necessary - unless you run worm resistant sheep or your resistance problem is already extreme.