In this week’s crop protection blog, Bill Lankford, ADAMA’s herbicide technical specialist, explains why the precise timing and choice of pre- and post-emergence herbicides is vital for the successful establishment of winter rye and winter barley.
As with any crop, the fundamentals of successful weed management in rye and barley are based on selecting the correct active ingredients for the task at hand and applying these products at the optimum timing.
Unlike wheats which can be drilled after the first flushes of grass weeds have been destroyed, rye and winter barley both need to be drilled earlier in the autumn to enable them to establish and produce tillers ahead of harsher winter weather. This therefore makes them less compatible with the tactic of drilling into stale seedbeds, and, as such, they should be selectively sown on land with a lower burden of grass weeds.
Rye and barley are also at a disadvantage compared to wheat thanks to a narrower choice of approved herbicides. The smaller seed size of rye, and therefore its shallower drilling depth, further complicates matters, with care needed to ensure pre- and post-emergence herbicide treatments don’t detrimentally affect the germinating seed and young seedlings.
While the number of herbicides approved for use in rye and barley is limited, ADAMA has developed a good range of options with products such as Tower, Anthem and Hurricane offering a wide breadth of label approvals.
Winter barley herbicides
With three proven and complementary modes of action (250 g/l chlorotoluron, 40 g/l diflufenican & 300 g/l pendimethalin) and two application timings (pre- or early post-emergence), Tower offers a simple solution for the control of Annual Meadow Grass and difficult broadleaved weeds in winter barley – either as a standalone product or as part of a programmed approach. The inclusion of chlorotoluron (unique to ADAMA) gives good residual activity in a range of soils and weather conditions and helps to mitigate the risk of resistance.
Anthem (400 g/l pendimethalin) is ADAMA’s SC formulation which delivers higher efficacy on grass weeds compared to CS formulations of the same active ingredient. This user-friendly product is easy to pour and rinse and can be used up until BBCH 30 to provide a broad spectrum of weed control.
Hurricane (500 g/l diflufenican) delivers proven broadleaf weed control and can improve the efficacy of some grass weed herbicides. It also boasts excellent residual activity which provides enhanced weed control even in dry conditions where germination is protracted.
Iconic (500 g/l flufenacet) is another useful residual herbicide for the control of annual meadow grass, black-grass and some broad-leaved weeds.
Topsail (800 g/l prosulfocarb) is a useful addition to winter barley programmes. Used as a pre-emergence treatment it offers good control of annual grass weeds and annual broad-leaved weeds.
Winter rye herbicides
Tower’s three-way mixture of 250 g/l chlorotoluron, 40 g/l diflufenican and 300 g/l pendimethalin makes it particularly useful for controlling grassweeds in rye, with its preferred timing for application being at the early post-emergence stage (GS10-11).
Hurricane (500 g/l diflufenican) can be used with Tower to add extra protection, up to a suggested maximum diflufenican rate of 100 gai/ha.
Topik (240 g/l clodinafop-propargyl & 60 g/l cloquintocet-mexyl) plus oil can also be used after Tower to provide additional control of wild oats from BBCH13-14.
Anthem 400 g/l pendimethalin is approved for use in rye. However, because of the vulnerability of young rye seedlings and the selectivity of shallow germinating seeds, Anthem isn’t always compatible with rapidly emerging crops. It shouldn’t therefore be used on lighter sands, stony or gravelly soils as any sudden heavy rainfall events will wash the active into the crop’s rootzone where it could cause significant damage to the developing plant.
Iconic (500 g/l flufenacet) has an EAMU for use in rye, but growers are advised not to use it in crops which have been drilled to a depth of less than 20mm. Similarly, growers should be wary of high flufenacet loadings: it is preferable to limit the total dose to less than 240 gai/ha at an early post-emergence timing at BBCH 11-13.
Spinnaker (800 g/l prosulfocarb) is a useful addition at early post-emergence timing (BBCH 10-11) but can only be used in rye under an EAMU (EAMU 20191754) up to 3.0 l./ha.*
* Neither the efficacy nor the phytotoxicity of Spinnaker for which an EAMU has been granted has been assessed and, as such, the user bears the risk in respect of failures concerning its efficacy and phytotoxicity.