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South Australia worms, flies and lice update - October 2014

Adelaide: Colin Trengove, Sheep Health Lecturer (UA Roseworthy campus) (trengovet@icloud.com)

Since Hughie flicked the switch in early August soil moisture has steadily declined and this has inevitably reduced pasture yield and advanced senescence of crops and pastures alike. Correspondingly, worm egg counts have diminished as worms are very astute at reducing egg output in response to season change. 

Rainfall records indicate 1914 is the last time SA had such a dry finish to the year from August onwards and a severe drought followed at that time. That is little joy, but an El Niño has been predicted since April at least. 

The only WECs indicating a need for a drench i.e. > 100 epg at this time of year have been hoggets in higher rainfall areas. That is ignoring wearers that are normally drenched at weaning. 

Seasonal conditions will predictably reduce the need for summer drenching, but WEC monitoring should continue to ensure no worm burdens are overlooked. In addition, summer rainfall can still produce unseasonal surprise worm burdens—especially Haemonchus (barbers pole worm).