1. Introduction
A series of experiments in winter wheat that started in 2005 have been examining the effect of different factors on doses of epoxiconazole (Opus) required to achieve effective control of septoria leaf blotch, and optimum yields and margins (calculated as yield x grain price minus fungicide cost).
1. Number of sprays - a single spray at T2 (GS39) or a well-timed two-spray programme at T1 (GS32 or leaf 3 emerged) and T2
2. Adding mixture partners at T1 and T2 - pyraclostrobin (as 0.5 l/ha Vivid) and/or chlorothalonil, (as 1.0 l/ha Bravo)
3. Varietal susceptibility to septoria, using Consort, Einstein and Robigus, rated 4, 5 and 7 (6 in 2007) respectively on the HGCA Recommended List for winter wheat
4. Site and seasonal differences in disease pressure, represented by four sites around the UK (Berwickshire, Norfolk, Hampshire and Herefordshire)
2. Results: Impact of number of sprays and mixture partners
3. Results: Impact of varietal susceptibility and site/seasonal disease pressure
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