Article taken from Farmers Guide, November 2017.
Black-grass is not a serious problem for most growers in my area of Norfolk. Unlike many others battling with the weed, they have been able to take advantage of the drier spell in late September and early October to push on with winter wheat drilling.
Seedbeds have been very good and, on the whole, these early drillings have got away well. However, at the time of writing in the first half of October, we'd had more than our share of windy weather.
Sprayers have been parked up rather than applying pre-emergence herbicides, and growers have chosen to push on with drilling to make the most of good conditions.
Applying the pre-em recommendation at early post emergence will still achieve good control for broad-leaved weeds, helped by the fact that most weeds have been slow to emerge, including black-grass due to high dormancy levels.
Growers without black-grass can use PicoMax (pendimethalin + picolinafen) and some additional diflufenican (DFF) pre-or postemergence will take out most major broad-leaved weeds and annual meadow grass. They also have the option of Othello (DFF + iodosulfuron + mesosulfuron) as a very good broad-spectrum back-up.
After drilling
Where black-grass has been increasing in prevalence the aim is to apply pre-ems as soon as possible after drilling. My programme is based on Trooper+ Herold, to supply 240g/ ha of flufenacet, backed up with pendimethalin and DFF.
This, plus Avadex (tri-allate) applied as soon as possible afterwards, will provide adequate pre-em weed control for most fields in my area.
However, if forced to go post-em, be sure to leave out the Avadex - this is a pre-em option only on.the label. Do take account of crop size and check with your agronomist that it is OK to proceed with other chemistry in the recommendation.
Growers with a more serious black-grass problem, as well as those growing second wheats (take-all was widespread in these crops last season), have been holding off drilling. I would urge them to continue to do so, well into November if possible.
A good quality seedbed will still be key to achieve optimal results. Soils should be rolled after drilling, unless they are prone to slumping - the last thing you want is to spend money on an expensive herbicide programme, only to find that clods fall apart, enabling weed seeds to germinate and establish.
The flufenacet-based programme mentioned above will provide a good start where black-grass has become more established. Adding prosulfocarb can increase black-grass kill by a few percentage points and boost control of problem ryegrass.
Following up with a further flufenacet application plus Xerton {ethofumesate) with help tidy up survivors. Or, in this area at least Atlantis {iodosulfuron + mesosulfuron) can still add some useful additional control in late autumn through to spring.
Sugar beet has been performing well this season, although harvesters are returning quite a lot of tops. Letting them wilt can save a lot of bother when it comes to drilling and crop emergence.
Maize has also had a cracking year, with yields averaging around 46t/ha, well above last year. Crops received moisture at regular intervals and there was enough light and heat for them to develop well.
Stand-out varieties so far are Susetta and ES Cluedo, both of which performed well on light soils, surpassing expectations. Forage variety Nordic Star has produced big yields on medium soils, with large cobs and good digestibility.
Craig Green is an agronomist with Agrovista, based at Great Ellingham, Norfolk (Craig.Green@ agrovista.co.uk).