Worm Heat Map – December Edition

Worm counts remain elevated in November following the dramatic rise seen in October.  It is worth noting that WECs at this time are significantly higher than counts at similar times in 2023 and 2024.  As summer storms persist, producers are advised to stay alert. Worm egg counts above 1000 epg are associated with higher rates of mortality.

In the central NSW region, worm challenge on the eastern side has risen (average WEC 567 epg) and the area is now shown in orange. Individual submissions have been variable, with over 20% over 1000 epg, but 80% below 500 epg. In the western zone, worm pressure is slightly lower, with an average WEC of 321 epg.

In the south of NSW, worm burdens remain at similar low levels to previous months. Most WECs are under 250 epg, indicating low challenge. For this region, the Wormboss drench decision guide advises treatment around cereal harvesting or before sheep are moved onto stubble. In dry years (or years of low challenge as the data indicates), to minimize development of drench resistance, WormTest adult sheep first and only drench if egg counts exceed 150 epg.

The worm challenge across most of Victoria remains low with the entire state shown as green on the map. 

The 1^st summer drench should have been completed by now. but be prepared to monitor worm challenge over summer.  A second summer drench will help to reduce contamination of pastures that impact autumn lambing. Treat if WECs are greater than 100 epg.

In the south-east, worm pressure has jumped to it highest level since February 2025, with an average WEC of 246 epg  reported. In this region over 13% of samples were above 500 epg, indicating a high worm challenge for some flocks. Worm pressure in the remainder of the state remains low. Worm advice for the region is similar to above.

In Western Australia's central region, the worm challenge remains moderate, while risk has increased to high in the southern region (shown in orange). A reminder that hoggets and weaners still require a summer drench in WA.

Sheep producing regions in the high rainfall of Tasmania have seen another rise in worm challenge, with the average worm egg count for the month at 515 epg. In the low rainfall region, samples returned in November indicate a low worm challenge.