Product Selection Advice for late Cereal Fungicide Strategies
With anti-resistance strategies becoming ever more important as new mutations continue to be detected in Septoria populations in the UK and Europe, Dr David Ellerton offers key advice
Dr David Ellerton, Hutchinson’s Technical Development Director, offers guidance on the best flag leaf fungicide strategies for this season in both wheat and barley, tailored to disease pressure and including strategies designed to minimise the risk of increasing fungicide resistance. Options for the final T3 ear spray are also considered.
The flag leaf or T2 fungicide application is often the most important fungicide timing in winter wheat, consistently giving the most profitable yield responses.
Moderate disease levels in wheat in 2018 due to the hot, dry summer generally resulted in cost effective but lower yield responses to fungicide programmes than the previous season. In Hutchinsons’ winter wheat variety trials, the average yield response across sites and all varieties was 1.54 t/ha (17.28 % of final yield) compared to 2.64t/ha (28.48% of final yield) the previous season. As usual, there was a significant difference in response between varieties with Reflection giving a response of 2.67 t/ha, while disease control in Santiago, Costello, Leeds,LG Rhythm and Gleam resulted in an increase in yield of over 2 t/ha (see table 1 on page 2). Despite the dry conditions later in the season, the largest yield increases were often in response to the flag leaf or T2 timing in Hutchinsons small plot trials, although drought and subsequent early senescence reduced the response in many cases.
Timing of flag leaf sprays
The purpose of flag leaf sprays is to ensure that disease is controlled on the top two leaves, which contribute approximately two thirds of final yield in winter wheat (see figure 1. right). Timing is critical and should not be delayed beyond the stage at which most flag leaves on main tillers have emerged (GS 37-39), usually in mid to late May.