Worm Heat Map – February Edition

Despite the northern tablelands having a very dry summer, average worm egg counts (WECs) were extremely high in February, with an average above 2000 epg. This was a significant increase from January, when the average WEC was less than 1000 epg, but much lower than February last year. On the western slopes and plains, the average WEC was the lowest it has been in February for a few years, with an average of 533 epg, shown as orange on the map.

March is the time to take action to ensure that spring lambing paddocks have no sheep worm eggs deposited on them during autumn. The combination of grazing management in autumn, followed by climatic changes in winter, prevents pasture contamination that would otherwise be the source of worm challenge for ewes and lambs later in the year.

In central NSW, worm challenge on the eastern side remained high over January and February (average WECs of 479 and 521 epg respectively), and the area is shown in orange.

In the west, the February average is the lowest it has been for five years and is shown as green on the map.

In southern NSW, worm burdens in the eastern zone increased over summer from a low in December (130 epg) to their peak in February (264 epg). As with northern NSW, these averages were still much lower than those recorded over a similar period last year.

In the west, worm burdens also increased over summer, with a higher average count recorded in February (445 epg). Looking at rainfall data, it is difficult to see how this area recorded higher WECs than the eastern zone, as it experienced below average rainfall.

Worm testing in this region is important 4–6 weeks after significant rainfall events, especially when there have been multiple rainfall events. Treatment thresholds are based on stock class and type of worm challenge (see Wormboss Drench Decision Guide).  Obtaining a larval culture to accompany a WEC at this time of year will help determine whether you can use a low treatment threshold (less than 60% barber’s pole worm) or a higher threshold (greater than 60% barber’s pole worm).

Worm challenge across northern Victoria remains low, with the entire state shown as green on the map. Remember to sample 4–6 weeks after the autumn break to keep worms under control.

In south west Victoria, the average WEC rose over summer. Starting from a low burden (137 epg), average WECs increased to 326 epg in January and 396 epg in February. Jumping in too early with a summer drench (e.g., November) can often result in reinfection and pasture contamination over the summer.

In Gippsland, the average WEC was also high for this time of year (359 epg), and the area is shown in yellow.

In the south east, December rainfall appears to have driven a rapid rise in WECs, with the January average jumping to 588 epg, and the high challenge continuing in February (420 epg). The area is shown as orange on the map. If sheep are grazing irrigation, be wary of barber’s pole worm successfully developing under these conditions. Across the region, conduct WormTests at 6–8 week intervals until pre lambing, and treat if counts exceed 200 epg in late summer/early autumn.

The Fleurieu and Eyre Peninsulas, are shown in yellow, indicating overall lower worm burdens than in the south east. On the Eyre Peninsula, worm burden peaked in December, was low in January, and has since returned to a moderate risk level. On the Fleurieu Peninsula, a different pattern was seen, with worm burdens starting low in December and rising to moderate risk levels in January and February.

The Yorke Peninsula is shown in green, although average counts have been rising since December.

In the southern region of WA, worm burdens were extremely high over the summer period. Averages for December and February were  above 1200 epg. In a region that received some summer rainfall, these high counts suggest that barber’s pole worm is currently a significant issue for several producers. The region is coloured dark red, representing a very high risk.

In other parts of WA, worm burdens appear more controlled. In the central agricultural zone, WECs have remained low all summer. In the south east, although data is limited, high counts earlier in the summer appear to be coming under control, with the average WEC dropping from above 1000 epg to 245 epg. Continue worm testing, especially 6 weeks after the autumn break, and treat if WECs exceed 300 epg.

In the low rainfall region of Tasmania, average WECs rose sharply in February to 252 epg, the highest since May 2025. In the high rainfall region, average WECs declined over summer, with February showing an average of 180 epg. This region is shown as green on the map to indicate low worm risk.