Following generally strong autumn weed control, growers must now decide how best to
manage surviving and spring-emerging grassweeds.
Hutchinsons technical manager Dick Neale says residual herbicides have performed well
overall. In the main, weaker results have largely been limited to early-drilled crops or where
dry conditions restricted activation.
“In many dry situations, lower-cost products were used initially, followed by more robust
residual options once rainfall arrived,” he explains. “That strategy, combined with wider use
of mixtures containing cynmethylin, bixlozone, aclonifen, metribuzin, flufenacet and
diflufenican, has driven improved control.”
Sequencing has also played a key role. Follow-up residual applications, applied when
conditions allowed, significantly strengthened overall performance. Gradual wetting and
mild weather supported active weed growth, aiding uptake without excessive leaching.
Cultural control has further reduced blackgrass pressure, he points out. “Even where drilling
dates were stretched, lower background populations meant residual chemistry faced less
pressure. In many cases, seed return in 2025 was minimal – something to bear in mind if
pressure rises again in 2026,” he adds.
Spring decisions
He says choosing between spring residuals and contact ALS herbicides depends on weed
species, growth stage and expected spring emergence.
“Pendimethalin remains the main spring residual option. It controls spring-emerging
blackgrass, ryegrass, wild oats and bromes, as well as broadleaved weeds. It is the only
residual available up to GS30 in winter cereals (aside from limited stocks of Lantern).
“However, established grassweeds will not be controlled effectively by residual chemistry.
ALS products remain highly effective on bromes and wild oats when applied before stem
extension. Control of established blackgrass and ryegrass will be poor, and early applications
may miss later-emerging weeds.”
Adjuvants, water and application
He share the results of recent trials underlining the importance of adjuvant choice.
“Increasing Phase II (95% MSO oil) from 0.5% to 1% with Broadway Star or Ultra improved
brome control by up to 20%.
Ryegrass responses differ though. “Adding Phase II alongside Biopower or Probe reduced
control from mesosulfuron + iodosulfuron products, whereas including 0.5% Validate
improved ryegrass control by up to 30%. For these mixtures, Biopower or Probe must be
included as per label, with Validate used additionally where appropriate.”
He notes, leaf drying within three to four hours is essential for contact products. “With
crops and weeds continuing to grow, applications should be made promptly when
conditions allow.
“Water quality is also critical. ALS graminicides respond well to conditioning, and most
water supplies will benefit from treatment.”
Finally, nozzle choice must not be overlooked, he says. “Most labels specify a medium spray
quality; very coarse 3-star LERAP nozzles will compromise whole-field performance. Correct
setup remains key to consistent, reliable weed control this spring.”
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