Black-grass remains the biggest issue in wheat, oilseed rape and other crops and it may be getting worse each year; resistance to herbicides is increasing, too.
As a result, growers are increasingly looking to place more emphasis on non-chemical methods of control such as rotations, delayed drilling, spring cropping, fallowing or grass ley breaks, competitive crops, and more effective use of rotational ploughing.
Paul Fogg, crop production technical lead at Frontier, says: “A high weed population can have real cost implications, as just 100 black-grass heads/m2 can create losses of one tonne per hectare.”
Variety selection, rotation choices, cultivation strategy and drilling date all form part of a successful, Integrated Crop Management (ICM) strategy, he emphasises. Combined with a robust herbicide programme, this will help reduce the spread of black-grass and protect future crops.
“Crop competition can be very effective, with high seed rates, narrow drill row spacing and more competitive varieties, for example hybrid barley, all proving beneficial,” says Dr Fogg.
“We know that Black-grass thrives in heavy, poorly drained soil” Paul Fogg
He emphasises the importance of mapping black-grass areas within the standing crop at this time of year to aid in decision making for next year’s crop.
“Stale seed-bed management, use of higher seed rates in the worst affected areas and the targeting of herbicide inputs, can all be implemented as a result of mapping black-grass.
“I would also suggest that growers look at the condition of their soil. We know that black-grass thrives in heavy and poorly drained soil, so alleviating compaction and implementing an effective drainage system can all aid in reducing the risk of black-grass and increased seed return. Again, this is something which can be planned ahead of the autumn drilling window where rotations allow.
“Last year, residual herbicide programmes worked very well, particularly when combined with delayed drilling, which generally afforded cool soil and good moisture levels.
“Stacking residual herbicides, built on a foundation of triallate and flufenacet, such as System 50, has also proved to be the most effective option.Winning Strategic Black-Grass Battles | Click To Tweet
“Flufenacet rates of 240 to 360 g/ha are now routine in bad black-grass situations, at pre-emergence or as a sequence, split between pre-em and post-em. Typically, flufenacet is co-applied with other residual actives such as pendimethalin and diflufenican, to add to the grass weed activity and widen the weed spectrum.
“It is important to review what has previously worked best on the farm, as well as understanding industry trials data, to ensure that growers are implementing the most effective herbicide programme this autumn.”