As Scottish growers continue to grapple with the season’s challenging weather, Interagro’s adjuvant experts stress the importance of precise and robust T3 sprays to safeguard crop yield and quality. Stuart Sutherland, technical manager at Interagro, underscores the critical role of T3 sprays, especially amid the widespread prevalence of septoria and rust in various wheat varieties.

Importance of T3 sprays

The T3 spray is the final opportunity to protect wheat crops, whether for milling or feed, from diseases and to optimise yield as harvest approaches. This season has been particularly tough for plant health, with wet weather promoting diseases like septoria. Yellow rust and brown rust are also present, depending on the timing and success of T2 sprays and local weather conditions.

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A well-timed T3 spray achieves three key goals:

  • Enhancing foliar disease control.
  • Protecting the ear against fusarium and microdochium.
  • Prolonging the green leaf area to extend photosynthesis and the yield-building phase.

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Timing and application

“Don’t wait until flowering has started in milling wheats as this will be too late to protect the ear effectively. As soon as ear emergence is complete, apply your fungicides,” advises Sutherland.

However, with unsettled weather conditions, achieving timely sprays can be challenging.

Ear emergenceEar emergence

Disease risks

Crops are at high risk now, necessitating proper fungicide applications with adequate coverage across the upper plant. Wet crops and windy conditions have moved septoria up the plant in many varieties, especially where earlier sprays were compromised.

Current conditions are ideal for fusarium infection, with warm (21°C) and wet weather breaking the dormancy of the fusarium fungus, leading to spore production. Spores can travel locally or from miles away, infecting exposed crops via the glumes/spikelets and potentially growing into the rachis, disrupting water and nutrient movement.

High humidity and warm conditions also favour infection, and the fungus can produce mycotoxins accumulating in the grains. This combination can lead to significant losses, making a timely and well-targeted T3 spray vital, especially for milling wheat.