Designing fungicide programmes for variety trials

Paul Gosling explains how we tap into a national network of agronomists to agree fungicide programmes that provide a fair test of varieties in trials.

Robust fungicide programmes are used in the Recommended Lists for cereals and oilseeds (RL) variety trials.

We aim to keep disease levels below 10% (in all varieties, in all trials) to show the potential of varieties across the UK (from Cornwall to Aberdeenshire) without variable disease pressures confounding the results.

Some suggest that the trials should use more commercially relevant or farm-standard programmes, but there are many reasons why this would not work, which I outlined in a recent article.

Although the aim of the fungicide programmes is clear, with new products authorised and others withdrawn, how we achieve it changes every year.

Each December, we gather a large group of BASIS-registered agronomists from across the UK to review the fungicide programmes to ensure they are fit for purpose (and legally compliant).

In a room full of agronomists (many with years of experience), you can imagine the debate.

Not all see eye-to-eye on the best products and rates to ensure that trials are properly protected from disease – no matter where trials are located or what the local disease pressure is.

There are valid reasons that underpin the varied opinions, especially when it comes to specific situations. This is why the RL’s fungicide programmes are never one-size-fits-all and have flexibility.

For example, we include optional products for specific situations, such as to deal with higher regional disease risks (like eyespot or mildew risks). The programmes also allow the adjustment of rates to match local disease pressures.

Ultimately, the programmes followed protect all the varieties in all the trials without unnecessary sprays or excessive rates.

There are also other unique challenges when designing a programme for a UK-wide trial system (compared to on-farm situations). For example, Brexit added complexity, with some products now only registered for use in Great Britain (GB). This means there is now some divergence in the programmes used in GB and Northern Ireland (NI).

We also aim to avoid products that may be withdrawn from sale (in the medium term), which requires a fair amount of informed guesswork.

Varieties recommended at the end of 2025 follow a fungicide programme agreed in 2024. Such varieties will be drilled by farmers in 2026, with some crops (e.g. winter cereals) not receiving sprays until 2027.

Designing fungicide programmes that account for so many elements is not easy to pull off. However, by tapping into a broad range of agronomist knowledge and experience, we get it right most of the time.

*The RL protocols page features the latest cereal fungicides protocol (protocol 201), which includes information on products, rates and timings.

The fungicide programmes are used in both the RL and the GB and NI Variety Lists (VL) trials, with the latter overseen by APHA (on behalf of Defra).