T2 fungicide choices for wheat crops

As crops approach the T2 fungicide timing, growers face a dilemma: which fungicide is likely to give the best protection for their situation?

The answer, says Dr Aoife O’Driscoll, Niab senior specialist in plant pathology, is reasonably straight forward: it depends on your priorities.

“Where Septoria is the dominant concern then Plaxium (fluopyram + isoflucypram + prothioconazole) at the full label rate is definitely on a par with Revystar XE (fluxapyroxad + mefentrifluconazole) and Univoq (fenpicoxamid + prothioconazole) for yield protection, and ahead of Ascra Xpro (bixafen + fluopyram + prothioconazole) in both efficacy and yield protection,” Dr O’Driscoll says.

“In Niab trials, Plaxium at T2 has delivered a yield response of 0.3-0.5 t/ha over that achieved with Ascra Xpro at the full label rate,” she adds.

Unfortunately, disease control is rarely mutually exclusive. Brown rust may not be the threat to crops it was last season; yellow rust certainly is.

“Where yellow rust is also a concern, and that would be the case in most situations this year, we see that the efficacy and yield protection delivered by Plaxium is comparable to Univoq and superior to that of Revystar XE and Ascra Xpro,” Dr O’Driscoll says.

Should conditions change and brown rust emerges as a consideration, the fungicide choices are more limited. This is largely due to only a few products offering credible broad-spectrum activity.

“We know there are issues with benzovindiflupyr that effectively discounts it from use against brown rust and that both Univoq and Adepidyn (pydiflumetofen), as in Miravis Plus, are not strong on this disease. In contrast Iblon (isoflucypram) and mefentrifluconazole are, so in such situations, the most effective fungicide choice is likely to be either Plaxium or Revystar XE.

“If you were looking for a broad-spectrum fungicide with good control of Septoria, yellow rust and brown rust, then Plaxium would be the most suitable choice, but if brown rust was the focus, Revystar XE would be the logical choice,” says Dr O’Driscoll.

Dry weather during the early spring meant there was little disease in crops as the T1 timing approached. This led to many growers diverging from the intended programme in the expectation of saving on costs. As the weather changed, this policy has left crops under protected with disease spreading rapidly from the base of the canopy.

The result is that crops typically fall into one of two categories: They are either the earlier sown crops with a high level of disease in the base or they are later sown with low to moderate disease pressure.

“Most crops fall into the latter category of low to moderate disease. In these situations, we see that Univoq at T1 followed by isoflucypram in the form of Plaxium at T2 as giving good all-round disease protection. Conversely, those crops carrying higher levels of disease will have benefited from Plaxium at T1 with a specialist Septoria product at T2,” Dr O’Driscoll says.

A new development within the 2025 season with the potential to impact fungicide programmes is the incidence of yellow rust in varieties thought to carry the YR15 gene. This is believed to confer all-stage resistance to yellow rust.

The varieties most notably affected include KWS Dawsum, LY Typhoon and LG Champion. These all showed strong resistance at the seedling stage in 2024 season but are now exhibiting more infection than some varieties acknowledged to have weaker resistance.

“The UK Cereal Pathogen Virulence Survey (UKCPVS) has also already received a surge of yellow rust samples from these affected varieties from others. We’re now working to determine whether this is the result of a new incursion of yellow rust from outside the UK, or whether we’re looking at a locally evolved race that has overcome previously effective resistance genes. Once the analysis is complete, findings will be published through AHDB,” Dr O’Driscoll says.

“The good news is that, for now, this race still appears to be controlled by tebuconazole when used as an eradicant in spray programmes. However, the virulence of this new race, particularly the speed at which it produces successive spore generations, remains uncertain,” she adds.

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Plaxium® contains isoflucypram, fluopyram and prothioconazole. Revystar® XE contains fluxapyroxad and mefentrifluconazole. Univoq® contains fenpicoxamid and prothioconazole. Ascra® Xpro® contains bixafen, fluopyram and prothioconazole. Miravis® Plus contains pydiflumetofen. Vimoy® (iblon®) contains isoflucypram. Plaxium, Ascra, Xpro, Vimoy and Iblon are registered trademarks of Bayer. All other brand names used are Trademarks of other manufacturers in which proprietary rights may exist. Use plant protection products safely. Always read the label and product information before use. Pay attention to the risk indications and follow the safety precautions on the label. For further information, including contact details, visit www.cropscience.bayer.co.uk or call 0808 1969522. © Bayer CropScience Limited 2025