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Disease Management

Bayer Crop Science

How to maximise disease control and yield from your wheat fungicide programme

Article overview

With the reduction in available chemistry, concerns around resistance and ever-increasing workload pressures, optimising spray timing and effective tank mixtures is more important than ever in enhancing disease control in cereals. Below you’ll find lots of resources to support you in optimising your disease control programme.

T1 Timing

Many diseases can damage your crop’s yield potential at T1. So it’s critical to get the timing right, and choose the best broad spectrum fungicide to keep your crop protected up to T2.

Potential yield loss from disease in your crop*:

*Source: AHDB

Getting the timing right

A T1 spray applied too early usually results in poorer disease control on the emerging leaf 3, due to a lack of coverage on the leaf as it emerges after application. Whereas, a T1 application applied too late will leave leaf 3 exposed to infection for longer. As a result, any fungicide will need to work harder to control latent Septoriaand can have a negative impact on product efficacy.

This video gives advice on how to get the best out of using a T1 fungicide to control disease in wheat, as well as how to pinpoint the correct timing for T1, and fungicide choice in different scenarios.  

Timing is important for T1 fungicides, so when should they go on?

For more videos on finding out more about maximising your wheat T1 strategy click here.    

Other factors impacting T1 strategy

In this video, Gareth Bubb, commercial technical manager at Bayer and independent agronomist David Lines discuss how factors such as variety susceptibility and drilling date can impact your T1 strategy.

Does T1 strategy alter by variety susceptibility?

Identifying eyespot at T1

With many varieties in the Recommended List having an inherent weakness for eyespot, being able to identify the disease is key to control at T1.  

In this video, Gareth Bubb, commercial technical manager at Bayer and independent agronomist, David Lines discuss how to identify the disease, and the weather conditions which may be conducive to its development.  

How do you identify eyespot at T1?

Identifying leaf 3

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.

Richard Cromie, an independent agronomist, says there are 5 key steps to identifying leaf 3 for fungicide timings.  To identify leaves:

  •      Cut one layer at a time

  •      Carefully peel back leaves

  •      Discard outer leaves

  •      Unroll all leaves to reveal the ear inside

  •      Note leaf three must be fully emerged before T1 spraying

Watch Richard talk through his advice on identifying leaf 3 in the following video:

How to identify leaf three in winter wheat in 30 seconds

What fungicides to use at T1?

In most situations with the reduction in efficacy from straight azoles, the best disease control will come from a product containing both SDHI and azole active substances. It is important to keep the rates of azoles in the mix up to at least three-quarter dose to maximise disease control from that component, while also helping protect the SDHI from resistance development.

Bayer’s Aviator (bixafen + prothioconazole) and Ascra (bixafen + fluopyram + prothioconazole) are formulated to provide the correct ratio of SDHI to azole, making them sustainable and cost-effective options. They both have Bayer’s Leafshield formulation technology, which uses a unique combination of adjuvants to improve crop coverage, leaf penetration and movement of active ingredients within the leaf.

Ascra is the best all-round option for T1 with good efficacy on all key disease including Septoria, Yellow rust and Eyespot. It can also reduce the need for a mildewicide. It offers good flexibility where you can adjust the dose rate to suit the circumstance. 1.0 L/ha will provide good control at T1 and it can be increased to 1.2 L/ha if there is an increased threat of disease.

Aviator is a cost-effective option on crops with lower disease pressure or where Eyespot is of particular concern due to the higher loading of PTZ.

Identifying latent disease

It’s important to know whether you have disease in the crop before you finalise your choice of fungicide at T1. But some diseases are hard to spot in their latent, or ‘non-visible’ stage. This is the period between a fungal spore landing on a leaf and germinating, and when disease is expressed on the surface of the leaf.

Septoria has a latent period of 15 – 18 days where you might not know whether disease is present.

Bayer has developed a new technology, CropCheck, which analyses leaf samples to detect the presence of Septoria and Yellow rust in the leaf tissue, and the quantity of any DNA that is present. The results are helping to inform growers and justify fungicide decisions.

We highly recommend:

  • Fungicides


    Ascra is a unique formulation of two SDHI fungicides – bixafen and fluopyram – and the broad-spectrum azole fungicide prothioconazole.

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