October
What's happening in wheat in October
While concerns about a repeat of the wet autumn of 2019 did prompt some growers to drill in the latter part of September, the majority have waited until October. This delay should have allowed plenty of time to remove any crop residues and achieve stale seedbeds, with at least one pass of glyphosate, if not two. Our germination map is plotting the emergence of black-grass up and down the country, so send in your updates via social media using #BlackgrassMap.
Grower should prioritise drilling according to black-grass pressure in each field, beginning with those with the lowest pressure, and targeting fields with the highest, later. Ideally, leave fields with the biggest black-grass problem until mid-October, when the main flush of black-grass is finished. A traffic light system of red, amber, and green can help visually prioritise fields on a map.
Aim to establish between 220 and 300 plants/m2 and adjust seed rate to account for grass-weed pressure, as well as soil type. Later-drilled fields may also need higher seed rates.
To reduce black-grass chit at drilling, sow at a depth that is appropriate for your land, but minimises soil disturbance. Rolling as soon as possible after drilling will help to consolidate the seedbed, break down any remaining clods and optimise the efficacy of pre-emergence herbicides that will be applied. Rolling can also reduce slug activity under the soil.
Apply pre-em herbicides promptly, ideally 24 to 48 hours after rolling, since black-grass will start to chit as soon as the soil has been disturbed by the drill. Apply a robust pre-em, such as Liberator, to soil which has sufficient moisture. This will aid residual activity in the active weed germination zone. Even where soils are drier than ideal, apply the pre-em at the same timing, since this will still be more effective at early weed control than waiting until rain arrives, or after the crop emerges.
Proclus is a new pre-em option to aid control of black-grass. It contains a new active, aclonifen, which can only be used at pre-em and in conjunction with Liberator, but provides an additional 15% of control.
To prevent potential crop damage from residual chemistry being washed into the crop rooting zone, growers should avoid applying residual herbicides to waterlogged soil or where heavy rainfall is expected.
Avoid big pre-em stacks, even in high weed pressure situations. Splitting treatments into two timings, pre- and peri-emergence, can be more effective and also reduces the potential for crop damage.
Finally, crops that were drilled in September may be at higher risk of Barley Yellow Dwarf Virus (BYDV). Growers should monitor crops closely in October for the presence of grain aphid and bird cherry aphid, and prepare to apply an insecticide if necessary.
Priorities now:
- Prioritise fields by weed pressure and hold off from drilling bad alack-grass fields until mid-October
- Apply residual herbicides promptly, for optimal pre-emergence control
- Monitor early-drilled crops for aphids and consider spraying to avoid BYDV virus transmission