Latest fungicide performance update includes new products and efficacy warnings

Jason Pole reflects on the latest fungicide data for septoria tritici in winter wheat, which includes efficacy data for a new product and fresh warnings about fungicide resistance.

Covering wheat, barley and oilseed rape, our fungicide performance work is consistently rated by levy payers as one of our most valued research projects.

Each year, the network of efficacy trials delivers a series of dose-response charts that indicate the relative performance of key fungicide products for major diseases (in terms of disease control and yield uplift).

To provide a tough test for fungicides, the trials are in high-pressure areas for the target diseases. The cereal plots also only receive a single spray (except where other diseases threaten to interfere with the results).

The trial design helps us tease apart performance differences.

As it is not possible to test every fungicide product, the trials focus on commercially important single active ingredients (and mode of action groups).

The results can help indicate how products may perform in the many potential combinations (products and doses) used in commercial fungicide programmes.

This year’s results for cereals were delivered by Jonathan Blake (ADAS) at the Agronomy Conference on Tuesday 9 December 2025.

The presentation also gave an update from our fungicide resistance monitoring project, which mainly monitors septoria tritici, due to its economic importance and vulnerability to fungicide resistance.

It started with a warning from the past, with charts showing the rapid loss of control associated with the quinone outside inhibitors (Qols/strobilurins) in the early 2000s (due to the G143A mutation).

It was a reminder of how quickly the resistance situation can change.

The 2025 update presented monitoring data for three major mode-of-action groups:

• Demethylation inhibitors (DMIs/azoles)
• Succinate-dehydrogenase inhibitors (SDHIs)
• Quinone inside inhibitors (QiIs)

The research uses septoria tritici samples (isolates), taken from wheat crops, and exposes them to various fungicide doses in the laboratory.

The isolates come from:

• Early season samples (before fungicide applications)
• Late-season samples (after fungicide applications)

The late-season samples are taken from winter wheat fungicide performance trial sites, which can indicate the specific impact of solo active ingredients on resistance (which should be avoided in commercial programmes).

In addition to providing annual information, the monitoring project also provides a valuable long-term data set (to identify trends) and determines the genetic underpinning of resistance (by using DNA-based markers).

Finally, the work also looks for signs of cross-resistance. This is where a pathogen develops resistance to fungicide products that were not applied (this can affect fungicides with the same mode of action).

Commercial fungicide programmes need careful design to slow resistance, especially to avoid the widespread selection of the least-sensitive isolates.

This is why it is important to use mixtures and sequences of different modes of action, which includes multisites (as they are less prone to resistance).

Folpet is now the only multisite authorised for use in cereals and it is not as effective as chlorothalonil was against septoria tritici (which was withdrawn in 2020).

The septoria tritici fungicide charts include folpet as a standard (as Arizona). We also use prothioconazole as a standard (as Proline 275). These are only tested at full dose.

As we have a good understanding of the performance of standards, they provide an excellent reference point from which to compare other fungicides.

In the trials, we also test products that have not yet reached the market. Once authorised, we can reveal how they compare with established fungicide products.

The latest fungicide performance results include efficacy information on the recently authorised product Jessico Fusion, which contains an SDHI (isoflucypram) and a QiI (fenpicoxamid) and can be used once each season.

These active ingredients have featured in previous fungicide performance releases, but it is the first time they have been combined in a single product.

For the second year, we have published key fungicide performance charts and summary pages online.

These are in addition to the full data set, available as a downloadable PDF on the fungicide performance homepage.

• Fungicide performance results for septoria tritici in wheat
• Fungicide performance results for rusts and fusarium in wheat
• Fungicide performance results for barley
• Fungicide performance results for oilseed rape
• Fungicide performance homepage

With options to protect chemistry eroding, we are running Resistance Roadshows this winter to bring together the latest thinking on the management of pest, weed and disease resistance.

We have an active research call for the next phase of fungicide resistance monitoring (the application deadline is 30 January 2026).