Nematodirus Forecast 2026 issued
Each spring, the Department of Agriculture, Food and the Marine (DAFM), in collaboration with Met Éireann, University College Dublin (UCD) and Teagasc advises farmers of the predicted risk of disease, chiefly in lambs, caused by the roundworm Nematodirus battus, through the Nematodirus Forecast.
In 2026, this forecast shows that the maximum Nematodirus egg hatching is expected to peak generally at the end of March and early April in many areas of the country, however, some inland areas will see maximum egg hatching around mid-April.
Results of this forecast can be used to gauge the optimal time to administer an anthelmintic (wormer) treatment to prevent disease. At-risk lambs (i.e. typically 6 to 12 weeks of age and grazing on contaminated pasture) should be treated approximately two weeks after the peak of Nematodirus egg hatching. Benzimidazoles (white drenches) are the treatment of choice for Nematodirus infections.