Disease control considerations for wheat at T2 approaches

Several weeks of mild and dry weather during spring has eased the disease pressure facing crops leaving many growers wondering what approach to take at T2. The variable nature of some crops and often regional nature of disease pressure, however, means there is no ‘one-fits-all’ answer, explains Jonanthan Blake, ADAS technical director and head of crop protection. 

After viewing the variety plots at Bayer’s Crop Doctor site for the east of England at Walpole St Peter, west of King’s Lynn, Dr Blake noted that “it’s difficult to have a general message. Some days favour brown rust sporulation, the next yellow rust while it would be unwise not to consider Septoria at T2, even in crops that appear clean”.  

“Yellow rust seems more prevalent here than Septoria at the moment, but Septoria has a long latent period of about 21 days, so while many crops look clean, they are still to see the effects of the rain that fell in the week before Easter,” he added.  

Looking through the varieties, it is possible to find examples of all the main foliar threats – Septoria leaf blotch, yellow rust and brown rust – just not all in the same variety. None of which should come as a surprise, but what does this mean for choices at the T2 timing?

“It’s likely in most cases to be a more protectant, rather than a curative situation; this simplifies decisions. Any of the main foliar threats could quickly take hold if conditions favour. The starting point is to base your treatment around active substances with good activity on Septoria tritici.   This could be SDHIs, azoles or QiIs, such as isoflucypram, mefentrifluconazole, pydiflumetofen or fenpicoxamid,” he said.  

To understand the protectant performance of fungicides against the main foliar threats, Dr Blake highlights the value of the AHDB fungicide performance curves.  

“The AHDB performance data give a clear representation of a fungicide’s activity against each of the main foliar threats. Some of these may be broader than others in terms of their spectrum, which may simplify the T2 application by reducing the need to add other chemistry,” he said.  

Short of the east of England experiencing an extended dry period, most crops will need something robust. Septoria and yellow rust are the obvious disease threats while brown rust is likely to present a local challenge in the more susceptible varieties.  

Thought will need to be given to which product best meets the disease complex and to what was applied at T1, notes Aleks Ćurčić, Bayer local technical manager for East Anglia.  

“For example, isoflucypram, fenpicoxamid and pydiflumetofen can only be applied once per season and this will determine T2 choices,” she says.  

“A good option for high pressure Septoria and rusts would be Jessico® One (fenpicoxamid) + Vimoy (isoflucypram), assuming neither active substance was used at T1. Pydiflumetofen, as in Miravis® Plus, is a strong option for Septoria but doesn’t match Vimoy® + Jessico® One against either yellow or brown rusts,” she adds.  

Where yellow and brown rust pose a greater concern than Septoria, an alternative would be Plaxium® (fluopyram + isoflucypram + prothioconazole). 

“Plaxium offers excellent all-round activity making it a reliable choice at T2 given the unpredictability of the season,” she says. 

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Jessico® contains fenpicoxamid. Vimoy® (iblon®) contains isoflucypram. Miravis® Plus contains pydiflumetofen. Plaxium® contains isoflucypram, fluopyram and prothioconazole. Jessico, Vimoy, and Plaxium 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