Wheat farmers have fewer and fewer herbicide options to use and the problems of weed control are increasing year on year. With the loss of popular actives, increasing weed resistance, restrictions in dose rates, complex sequencing and even problems of herbicide availability, wheat growers should explore alternative options and consider integrating a different herbicide into their weed control programmes this autumn.

"If we look at the active ingredient options we have available for the autumn, you can count them on the fingers of both hands – chlorotoluron, DFF, flufenacet, flupyrsulfuron, iodosulfuron/mesosulfuron, pendimethalin, prosulfocarb, triallate and flumioxazin (FMX). None of them can stand alone, as they all need to be integrated in a programme if acceptable weed control is to be achieved. This integration is not just to improve the control of competitive grass and broad-leaved weeds, but also to ensure the continued activity of the limited range of herbicides we have," says Dr. David Stormonth, Technical Manager for Interfarm UK Ltd.

Sold as Digital, flumioxazin is being put forward as a valuable and different option to consider this autumn, as it offers high levels of control of many difficult broad-leaved weeds plus excellent control of annual meadow-grass and, importantly, useful activity on black-grass.  "Digital is so straight-forward to use. It has none of the complications that many other autumn herbicides have and it is a dream to integrate along with other herbicide components in a programme. For a start, it can be used on all wheat varieties, with no varietal restrictions. It can be mixed with a range of other grass-weed herbicides, including Defy (pre-emergence only), Liberator or chlorotoluron-containing products, and can be sequenced with any other herbicide applied in autumn or spring. No varietal problems, no sequencing problems, no following crop restrictions and no cultivation issues makes it a particularly flexible herbicide to use," says Dr. Stormonth.

David explains that Digital also has good timing flexibility and can be applied pre-em or post-emergence. "If you are targeting black-grass, you generally have 3 specific lines of defence – pre-em, early post-em and late post-em. If you have time for a pre-em treatment, options to consider would be 100 ml/ha of Digital mixed with either up to 0.6 l/ha of Liberator or with 4 l/ha of Defy or with the appropriate rate of a chlorotoluron containing product. Alone flumioxazin pre-emergence offers between 30 to 40% control of black-grass, which becomes additive when mixed with other herbicides, the combination giving an excellent start to any black-grass control programme."

"At early post-emergence, when black-grass is still small and at the 1-2 leaf stage, the next treatment should build up the defence using products with different modes of action and with both residual and contact activity.  Digital fits well as it has strong contact activity as well as residual activity. Unlike some other herbicides, flumioxazin is taken up by the weed coleoptiles and leaves. It is also from a completely different chemical group, namely the PPO inhibitors in the HRAC group E. Digital can be used alone as a holding spray or can be mixed with a chlorotoluron-containing product or Liberator for improved grass-weed control. When applied post-em, crops need to be reasonably hardened to reduce any risk of foliar spotting."

"The final line of black-grass defence is applied either at the end of the autumn or early spring and there is just the one option based on iodosulfuron and mesosulfuron. Here you need to make sure that any herbicides that you have already used or are planning to use are OK to sequence with this ALS inhibitor. Reducing black-grass levels in the first two lines of defence makes it easier for the third and final defence line to work effectively."

Dr. Stormonth points out that flumioxazin is also a very useful option for annual meadow-grass control, applied either pre or post-emergence.  "Trials and commercial use show that it performs very well on annual meadow-grass, resulting in 95% control on average. For annual meadow-grass, Digital can be used alone or mixed with Liberator at just 0.1 l/ha.  With just one autumn treatment, you can spray and close the gate."

Digital excels in its ability to control broad-leaved weeds.  "In trials applied early post-emergence, it gave 100% control of charlock, chickweed, fumitory, field pansy, groundsel, ivy-leaved speedwell, mayweed and red deadnettle, 99% control of cleavers, common field speedwell and Shepherd’s purse, and 98% control of poppy. Additionally, users have reported very good activity against volunteer crops, such as beans and borage. No other wheat herbicideperforms to this level or offers that weed spectrum,"  he reports.

Note:

Digital contains 300 gm ai/litre flumioxazin, formulated as a white, non-staining, easy-to-use suspension concentrate, packed in a 500 ml pack. Recommended in winter wheat, it can be used pre or post-emergence up to before GS 15 for the control of a wide range of broad-leaved weeds, including charlock, chickweed, cleavers, common field speedwell, common poppy, field pansy, fumitory, groundsel, ivy-leaved speedwell, mayweed, red deadnettle and Shepherd’s purse, and grass-weeds, including annual meadow-grass and loose silky bent. It is recommended at 100 ml/ha in 200 litres of water, with one application per crop. It has residual and contact activity. It is compatible with a wide range of autumn products, but should not be mixed with any adjuvants or with pendimethalin containing products. It can be sequenced with any product including sulphonylureas, but a 14 day interval should be allowed. Don’t forget the use of a proprietary tank cleaner before and after spraying to thoroughly clean all spray equipment, including booms, pumps, filters and lids.