Aviator 235Xpro

The primary goal when applying a T1 fungicide is to control Septoria on the recently emerged final leaf 3 and leaf 4 at GS 31-32.

Timing is critical, with T1 sprays applied too early usually resulting in poor disease control on the emerging leaf 3 due to a lack of coverage on the leaf that emerges after application.

Optimum performance from T1 applications is seen after a T0 spray, typically applied two to four weeks before T1.

When T1 applications are applied too late, leaf 3 is exposed to infection risk for longer. This requires any fungicide to work harder to control latent Septoria when it is eventually applied and can have a negative impact on product efficacy.

The effect of timing was shown in NIAB and Velcourt trials which compared Proline + chlorothalonil with Aviator. Each was applied at a standard T1 timing following a T0 or after a five-day delay. Both sets of treatments were also applied where no T0 was applied.

Although yield response steadily decreased as the situation became more curative for both treatments, Aviator offered a significant yield benefit over Proline + CTL at every stage except when timing was spot on. 

Any rust and mildew present at T1 should be adequately controlled by Septoria-active fungicide products, but adding specific rust-controlling products to the sprayer tank may be required in a high pressure scenario.

T1 is also a key time to assess and reduce risk of stem-base diseases such as eyespot, Fusarium and Microdochium inoculum taking hold. Where risk is high, a product with good activity against these diseases should be considered.

Richard Cromie, an independent agronomist, talks through how to identify the emergence of leaf 3 in wheat which is critical for the accurate application of T1's.

This video gives advice on how to get the best out of using a T1 fungicide to control disease in wheat. Also, how to pinpoint the correct timing for T1, and what types of fungicide to use in different situations.

The curative efficacy of azoles including prothioconazole and epoxiconazole slipped around 2012 as the incidence of more insensitive isolates in the UK population increased. However, since then prothioconazole has stabilised relative to other azoles, and for the first time it is now clearly pulling apart from epoxiconazole in performance against Septoria.

ADAS trials, looking at a two-spray azole programme at T1 and T2 using prothioconazole, epoxiconazole or metconazole in 2016 highlighted its superiority. An application of Proline at 0.58 L/ha – the same dose as in 1.0 L/ha of Aviator or 1.2 L/ha of Ascra – gave a respectable 55% control of Septoria and a 1.0 t/ha uplift in yield. While the other azole products used in the trial – Rubric and Caramba – performed relatively well, prothioconazole gave a consistently higher level of Septoria control at low, medium and high rates. As a result, when epoxiconazole or metconazole are used in SDHI co-formulations such as Adexar and Librax, the SDHI component is working much harder than the azole to control Septoria. This added activity provided by prothioconazole is extremely valuable for the other actives in terms of resistance management.

In addition, prothioconazole is tried and tested on eyespot and when combined with bixafen in Aviator is boosted to control levels that supersede Tracker – widely seen as the go-to product in high eyespot risk situations at T1.

Fusarium, mildew and yellow rust can also threaten at T1 and although Aviator is still a good T2 option, its 80% dose of prothioconazole makes it a logical choice at T1 because of its strength on all those diseases.

1.0 L/ha Aviator ²³⁵_Xpro + 500g/ha CTL

Where disease pressure is higher, spot-on T1 timing cannot be guaranteed, or the T1 has been delayed, extra Septoria curative activity will be required and the addition of SDHI bixafen in Aviator ²³⁵Xpro will boost control, while also giving a physiological boost through crop greening.

Aviator ²³⁵_Xpro is also formulated with Leafshield technology, which uses a unique combination of adjuvants to improve crop coverage, leaf penetration and movement of the active ingredients within the cereal leaf.

Great coverage potential gives flexibility and confidence when using different application techniques, such as air induction nozzles or a lower water volume. It is also rainfast within minutes, providing consistent performance in challenging spraying conditions.

0.55 L/ha Proline ²⁷⁵ + 500g/ha CTL

While declining azole activity against Septoria has been well documented, primary azole prothioconazole still provides good control of the disease – particularly when applied in a protectant situation with multisite CTL.

• In a low disease risk scenario following a robust T0 and where spot on T1 timing can be achieved, 0.55 L/ha Proline ²⁷⁵ + 500g/ha CTL provides good control of Septoria, yellow rust, mildew, true eyespot and early season Fusarium and Microdochium inoculum.
• A late-sown variety with a good Septoria resistance rating of 7 on the AHDB Recommended List constitutes a low pressure situation in average conditions.
• If yellow rust has escaped the T0 timing and is active in the crop at T1, add a strobilurin to 0.55 L/ha Proline ²⁷⁵ + 500g/ha CTL to boost rust knock down.
• In more susceptible varieties (Septoria rating <7), where the T1 application is delayed, or in high early Septoria pressure seasons, substitute Proline ²⁷⁵ + CTL with Aviator ²³⁵_Xpro + CTL for added disease control provided by its SDHI component, bixafen.