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Tasmania worms, flies and lice update - November 2016

TAS WormBoss Worm Control Program

TAS WormBoss Drench Decision Guide

Perth: Paul Nilon, Nilon Farm Health (

What an extraordinary spring we’ve had! After about 3 weeks of constant, demoralising wind we had a few calm days before more widespread rain dumped on the state. The Macquarie and South Esk flooded for at least the fifth time this year. Fortunately, many of the northern rivers that had catastrophic flooding in June escaped relatively lightly. The spring that was beginning to wilt under the incessant breeze is now rejuvenated and hay making has been delayed a bit.

The worms are still quiet. Egg counts have been astonishingly low. So, what more can be said? Well, as a person who once had the last say at Echo Point, here are a few thoughts and reminders.

Prime lamb weaning is now underway. Do not delay weaning (prime lamb or merino) unless you can reasonably expect numbers of suckers (in which case you can do a partial wean). Drench all ewes at weaning if they are going back onto perennial pastures.

The wet conditions make for a bumper fly season. For many years I have urged a risk management approach to fly treatments rather than “all sheep/every year/same date”. This year the risk will be high, particularly if the winds disappear (which will also aid the fly fishing). So, in anticipation of lots of Lucilia, and the prospect of getting away to wave the wand, I suggest you give thought to treating early, or moving shearing and crutching forward to get protection. Chemical choice is, as always, determined by the balance between duration of activity, wool and meat withholding periods and the time until the next crutch or shearing. Even with a crutch, autumn and winter-shorn ewes will be at risk of body strike as moisture pools on their ever-so-fat backs.

Medium merinos are vulnerable to dermo. In wet years it thrives: if you spring/summer shear these sheep get them out of yards ASAP after shearing. One-year-old sheep may be well infected with dermo. On most places it’s obvious, but some flocks may have a few covert patches on sheep of all breeds that will attract flies like seagulls to chips.

Finally, the huge spring has set the stage for a good Haemonchus year. The north-east and Tamar can expect this worm soon after Christmas. Irrigated properties around Cressy, Hadspen and Hagley should be alert. Look for high egg counts but without an attendant scour. Also keep in mind that our repeated flooding may expand fluke habitat. Marshy areas on the lower Macquarie and Esk will almost certainly have had intermediate fluke stages and snails washed down from the chronically infected areas in the highlands. More on this in the next few months.

For November 2016 state outlooks, please follow the links below:
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