Introduction

Where is the South Australian winter rainfall region?

In South Australia, there are 3 zones within the winter rainfall region. Information for these 3 zones is in this article.

In addition, there is a much drier Pastoral zone, covering areas to the north of the Lower Rainfall Mediterranean zone (generally north of Goyder’s line), and for which information on worm control is in WormBoss regional worm control program, Pastoral. A map of the region is shown below.

The South-East zone

This zone is the south-eastern corner of the state below an approximate line running from Kingston SE to Bordertown, through to the Victorian border. The zone generally receives more than 550 mm annual rainfall. Although summers are warm, effective summer rainfall episodes (12 mm or more) are not unusual, especially towards the coast. Pastures sometimes retain a substantial green component over summer.

The Higher Rainfall Mediterranean zone

This zone has the following areas:

• Kangaroo Island
• The southern tip of the Eyre Peninsula below Cummins
• Fleurieu Peninsula and the Adelaide Hills
• Clare Valley

Usually this zone receives more than 450 mm rainfall per year (though some areas are substantially higher) and summers are generally hot with no effective rainfall. Cropping can be a component of the enterprise mix.

The Lower Rainfall Mediterranean zone

This zone is north of the Higher Rainfall Mediterranean zone and extends to a line running from Ceduna across the Eyre Peninsula to between Cowell and Whyalla, then from around Port Pirie to south of Port Augusta, Orroroo and Peterborough, then east or north of Burra, Mannum, Karoonda to near Pinnaroo. This corresponds to Goyder’s line in many places.

It typically receives less than 450 mm rainfall per year and summers are usually hot with no effective rainfall. Cropping is a substantial component of the enterprise and most properties have stubbles or crop residues available for grazing.

The boundaries for these zones are approximations only as seasonal temperature and rainfall variations affect worms.

What worms are covered in this program?

Roundworms

The most important roundworms in this region are:

• Scour worms
  • Black scour worm Trichostrongylus vitrinus / Trichostrongylus colubriformis
  • Small brown stomach worm Teladorsagia (Ostertagia) circumcincta
  • Thin-necked intestinal worm Nematodirus species (only in young sheep)

In some or most years around Willalooka, Mundulla, Keith, Tintinara, Strathalbyn Plains, Adelaide Hills, Fleurieu Peninsula and coastal areas as well as isolated properties in the lower south east:

• Barber’s pole worm Haemonchus contortus

Very wet years generally cause higher burdens of all worms. These can be fatal without scouring occurring.

Liver fluke

Liver fluke is an internal parasite that occurs in limited parts of South Australia, but is usually associated with problems in cattle rather than sheep. When sheep are introduced from known liver fluke areas, include a triclabendazole drench (which is effective against all stages of liver fluke) with quarantine treatments for worms.

The life cycle differs from the simple life cycle of roundworms, so control strategies are different.

Other worms

Gastro-intestinal parasites of minor importance such as large bowel worms and tapeworm are not covered.