Choices aplenty for winter crop fungicides
Published 19/04/2011 | 05:00
The choice of fungicides available is huge and this article cannot cover all. Yet, the following will briefly outline possible fungicide choices for winter wheat and winter barley.
Septoria is the main disease of winter wheat. The main fungicide programme really starts with the T1, which aims to protect leaf 3 and leaf 2, both of which will contribute to final yield. Get the timing of the T1 application wrong and you will struggle to control disease all season.
Apply the T1 when the majority of leaf 3s are emerged. This is not necessarily at GS 31 or GS 32 but can be in between.
The target diseases at the T1 timing in winter wheat are septoria, eyespot (in continuous tillage ground) and, to a lesser extent, mildew. Include Chlorothalonil (Bravo) in all T1 applications. Use a high rate (80pc+) of a triazole or triazole mix at the T1 timing -- Venture Extra, Gleam, Tocata or Proline can be used. Cheaper products containing epoxiconazole could be used where eyespot is not set to be a problem.
The T2 or second main fungicide timing should be targeted at the flag leaf emerged. This will comprise of a high-rate triazole (80pc+) + SDHI + chlorothalonil. This timing generally returns the most money, therefore you should aim to spend the most money here. Target the use of a product containing a SDHI (Aviator, Venture Extra) as these have shown a higher yield in trials when used at this timing.
The final application (T3) will again consist of a triazole mix of products (Caramba, Folicur, Gleam, Prosaro, etc). These will give protection from fusarium (50pc control is regarded as good control). The addition of a strobilurin may be justified in high-yielding situations.
Start planning barley fungicide strategies early so that products can be purchased on time and at a lower cost. Generally, two fungicide applications are needed to keep disease at bay.
Varieties with good disease resistance, such as Quench, Propino or Magaly, can lend themselves to a low fungicide strategy, eg, reduced rates at both timings. Keep a close eye on Snakebite for rhyncho and Azalea and Cocktail for net blotch at an early stage.