With autumn fast approaching, attention is turning to winter wheat drilling and how to achieve the best possible grassweed control to get crops off to a strong start.
Black-grass and Italian ryegrass remain two of the most damaging threats to UK arable production. Even low populations can escalate rapidly, with just one plant per square metre producing 10 heads, each carrying around 1,000 seeds, adding up to six million seeds per hectare to the seedbank.
Drawing on his extensive experience, technical expert Stuart Kevis (BASF) shares his IPM Game Plan to reduce grassweed pressure, safeguard yields and protect cropping options for the future.
1. Enhance soil health
Black-grass thrives in cold, wet, poorly structured soils. Improving drainage, reducing compaction and addressing pH or nutrient imbalances all create conditions that favour crop growth over weeds. Organic amendments can enhance soil structure and water movement, while targeted fertiliser placement at drilling promotes rapid crop establishment and improved competitiveness. Cover crops can also help build soil resilience and reduce black-grass pressure across the rotation.
2. Reset seedbanks with ploughing
A well-executed ploughing operation can dramatically reduce surface seed populations by burying the majority of fresh seed to depths from which it cannot germinate. Rotational ploughing, carried out one in every five years, is especially effective against short-lived seeds such as black-grass. For long-term success, ensure inversion is complete and keep subsequent cultivations shallow.
3. Delay drilling to reduce pressure
Postponing drilling until at least mid-October in problem fields allows more weeds to emerge and be destroyed ahead of crop establishment. Delaying drilling by just one week in autumn can reduce black-grass pressure by approximately 15%. Later drilling also improves residual herbicide performance, as soils are more likely to retain the moisture needed for optimum activity, while late-germinating weeds tend to be less vigorous and produce fewer seeds. To make this strategy effective, prioritise clean fields first and ensure drilling capacity is in place for later, dirtier blocks.
4. Optimise stale seedbeds
Even after a good year of control, the seedbank carries substantial threat, but a well-executed stale seedbed remains one of the most reliable cultural controls. Shallow cultivations of no more than 5cm, followed by consolidation, encourage grassweed seeds to germinate. Subsequent cultivations or glyphosate applications then remove these flushes, lowering the weed burden before the crop is drilled. WRAG guidelines on glyphosate resistance can be accessed here.
5. Strengthen crop competitiveness
Crops that establish quickly and develop dense canopies are better able to suppress black-grass. Select vigorous varieties with rapid early growth, aim for high plant populations (>300 plants/m2) and use narrow row spacing to reduce gaps where weeds can emerge. Drilling rates should account for seed size, germination and soil type to achieve strong establishment, while timing must balance early crop competition with the benefits of delayed drilling for weed control.
6. Best chemistry first
Residual herbicides deliver their greatest benefit when weeds are targeted before emergence. Starting with the most effective chemistry at this stage, such as Luximo®, provides the strongest level of control and underpins the rest of the programme. In seasons where follow-up applications are difficult, this early investment in efficacy helps reduce long-term risk.
7. Apply herbicides responsibly and accurately
Accurate, timely spraying is essential for effective grassweed control. Pre-emergence products such as Luximo® work best when applied withing 24-48 hours of drilling to moist, well-consolidated, clod free seedbeds with minimal trash. Ensure at least 32mm seed cover and closed slots in direct-drilled fields. Use partner products for resistance management, follow stewardship best practice and maintain precise application timing to maximise efficacy and protect chemistry for the future.
Final word
No single tactic will solve grassweed challenges on its own. But when combined into a robust IPM game plan, these cultural and chemical measures can bring populations down to manageable levels, safeguarding yields today and protecting cropping options tomorrow.
Download the full BASF IPM Game Plan here.