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Monolith is a new post-emergence herbicide formulated to tackle black-grass. For use in winter crops during spring, it provides 10% more control than Atlantis against black-grass. It partners two actives with exceptional grass-weed activity – mesosulfuron and propoxycarbazone. This combination means Monolith has the power to control a wide spectrum of grass-weeds on top of black-grass.

Monolith is the final stage of a black-grass control programme following on from cultural controls and a robust pre-em. Use Monolith in spring from the 1 February and when the crop is at 3-leaf stage until 2nd node detectable (GS12–32).

Uptake is mainly through the shoots so there needs to be some active growth for the herbicide to take effect; care is needed for applications in February when conditions may be cold. Weather conditions at application are very important; apply to a dry leaf with sufficient drying time before dew forms.

Like other Bayer post-ems, applying Monolith when the target weed is small increases the overall level of control but conditions need to be right. Applying in cold or wet conditions is not advisable even if the plant is small because the active substances will not be taken in effectively.

It is often said that the control from herbicides is 50% chemistry and 50% application and Monolith is no exception. The aim is to land the herbicide on the target leaf so it settles, dries and is taken in by the plant. To do this a fine spray, possibly fine-medium is required. Generally, the flat fan type nozzle produces a finer spray than the air inclusion nozzle.

Forward speeds should be no more than 12 km/h and make sure the sprayer boom remains stable to get a consistent application. Water volumes of 200 L/ha are suitable for Monolith. 

All applications should include 1 L/ha of the adjuvant biopower. There is also the option to include 0.3 L/ha Liberator as residual protection if you are expecting further spring germination of grass-weeds.

Every bit of control counts when fighting black-grass. At first glance, 10% more control may not seem an enormous amount but it means less competition for your crop and fewer seeds returned the following year. In trials comparing Monolith and Atlantis, Monolith resulted in 28 fewer black-grass heads as the graph shows.

Crucially, these differences in head number affect yield. Based on AHDB Project Report 560 (Sustaining winter cropping under threat from resistant black-grass),

we can calculate that 30 fewer heads /m2 boosts yield by 0.3 t/ha. A useful boost to production and fewer black-grass seeds returned to the field too. The image below the improvements in control from Monolith against a range of grassweed at our Chishill weedscreen.

The final point, is that Monolith’s exceptional grass weed control is at the expense of some activity on broad-leaved weeds so consult the label before making the switch if you have been using Atlantis as an all-purpose spring herbicide.