Fungicide strategies for the control of Ramularia collo cygni to optimise grain yield and quality on spring barley in Ireland

摘要

Leaf blotching and spotting has been a widespread and commonly occurring phenomenon on spring barley in Ireland from 1997 to date. In 2000 the fungal pathogen Ramularia collo cygni was identified as the dominant causative agent of the late-season Ramularia leaf spot. In the years 2000 and 2001 fungicide strategies based on triazole and strobilurin chemistry gave inconsistent and often sub-optimal control of this disease. Since this time strobilurin fungicides are not used specifically for the controlofRamularia leaf spotting with current fungicide strategies combining triazole chemistry and the contact fungicide chlorothalonil. In 2002 high levels ofRamularia infections were widespread on spring barley in Ireland and the most effective triazole plus chlorothalonil treatments gave grain yield responses in excess of 21 ha'1. Triazole plus chlorothalonil fungicide mixtures applied at Growth Stage (GS) 39-45 are the basis of current agronomic advice to growers in Ireland.