AGRONOMY UPDATE

A Challenging Start to Spring for Winter Wheat

Spring has been tough for winter wheat crops. Soil temperatures have taken far longer to warm up because of excess water. Normally, at this time of year, soils would be around 12°C. In early May, they were only 9°C. On top of that, stressed crops have suffered more chemical damage and liquid fertiliser stress than usual.

Rust Pressure and T1/T2 Trends

At T1 timing, stressed crops showed early rust infections, yellow and brown, compared to fitter crops of the same variety. This trend has continued into T2. Even the most robust T1 applications only held rust at bay for two weeks on susceptible varieties. In many cases, a T1.5 spray was needed, costing between £5/ha and £30/ha depending on whether an SDHI was required.

New Varieties Shine

On a positive note, new varieties with strong disease profiles, such as Extase, Palladium, Typhoon, and Champion, are looking clean and healthy! This week marked the first main wave of T2 applications, but wet weather has slowed progress. Most T2 sprays will now go on next week. Because of the huge drilling window caused by the wet autumn, some farms will apply T2s over a four-week period.

Septoria Situation and Product Choices

Surprisingly, septoria infection is far less severe than expected, despite heavy rainfall (it spreads via rain-splash). For T2, any of the strongest actives for septoria, fenpicoxamid, mefentrifluconazole, adepidyn, are suitable this year given current disease pressure. The choice will largely depend on the variety and its rust protection needs.

If the variety is susceptible to brown rust or rust is active in the crop, add an extra product such as tebuconazole, azoxystrobin, or pyraclostrobin. For the dirtiest varieties, consider additional brown rust protection with benzovindiflupyr.

Other Priorities

Current priorities also include:

• Sugar beet herbicides
• Spring cereal treatments
• Protein applications on wheat

If you’re growing a rust-susceptible variety, its T2 must take priority.

Top Tips for Managing Wheat Disease

• • Check variety scores: They are performing true to score this year. If susceptible, protect them.
  • Watch timings: Do not rely on any application to protect against rust for more than two weeks this season.
  • Add eradicant action: If you have a susceptible variety or active rust, include an active with eradicant properties.
  • Reduce stress: Minimise stress from non-disease factors such as micronutrient deficiencies.