HUTCHINSONS FieldWise(May2019) - Page 1



Fieldwise
AGRONOMY NEWS FROM
MAY 2019
The Importance
of Late Cereal
Fungicide Strategies
Dr David Ellerton
TECHNICAL DEVELOPMENT DIRECTOR
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.
Ear
Flag Leaf - Leaf 1
Leaf 2
Leaf 3
Leaf 4
Leaf 1
0 5 10 15 20 25 30 35 40 45
Contribution to yield (%)
Fig. 1. Contribution of Leaves and Ear to
Final Yield in Winter Wheat. Source: AHDB
Although disease levels will vary
between crops and varieties, it is
vital to control disease before it gets
established - particularly Septoria tritici.
>

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