T1 lays the foundation for big wheat yields

The key to a successful wheat fungicide programme is starting off on the right foot.

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

What is the aim of a T1 fungicide?

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.

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.

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.

T1 PRODUCT CHOICE AND BEST PRACTICE

Medium to High disease risk – 1.0 L/ha Aviator ²³⁵_Xpro + 500g/ha CTL

Using 1 L/ha Aviator ²³⁵_Xpro + 500g/ha CTL at T1 will bring all the benefits of 0.55 L/ha of Proline ²⁷⁵ + 500g/ha CTL, but with increased septoria, brown rust and eyespot activity and physiological benefits that the addition of SDHI active bixafen can offer.

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.

• Where a T0 has not been applied, the T1 application is delayed, or both, Aviator ²³⁵_Xpro + CTL will give better and more consistent disease control and yield response than Proline ²⁷⁵ + CTL across a range of situations.
• If a T1 application containing Aviator ²³⁵_Xpro is delayed between five to seven days after leaf 3 is fully emerged, do not mix with CTL to increase curative activity on latent Septoria infection.
• Where rust is established and active in the crop, substitute CTL for a rust active strobilurin, such as pyraclostrobin.

Low disease risk – 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.

Aviator ²³⁵_Xpro at T2

• Where the T2 flag leaf spray is well timed and in a low to moderate Septoria pressure scenario, Aviator ²³⁵_Xpro provides a cost-effective T2 solution. There is no requirement to add a multi-site fungicide at this timing.
• For higher disease pressure, Ascra _Xpro is the recommended product at T2.