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What are the toughest targets?

The Bayer spray survey spoke to over 200 operators about the hardest targets to time and physically hit. 61% of spray operators said it is hard or very to hit grass-weeds with a post-em in spring while, 47% said it is quite hard or very hard to apply the spring post-em herbicide at the correct time. 

In the entire survey, weed control in sugar beet was the toughest target with 69% of spray operators saying it is quite hard or very hard to time applications and 73% saying it is fairly challenging or very challenging to hit the target. Apart from spring grass-weeds in cereals, other tough targets included propyzamide / carbetamide applications in oilseed rape and potato blight sprays.

A survey of over 200 spray operators revealed that post-emergence grass-weed control in wheat is one of the hardest spray targets for both timing and accuracy. With applications of Monolith and Atlantis WG against black-grass imminent, here are six essential steps to get the most effective application this spring

1. Preparation

Make sure the sprayer is ready to go at short notice. Spray windows can be short so don’t lose time adjusting the sprayer when you could be out in the field. Check boom stability, nozzles and filters well ahead of time so no opportunity is wasted to control black-grass.

2. Patience

Dew is the enemy at this time of year. You have to wait until it dries off before applying the herbicide and then leave a long enough drying window before dew formation in the evening. Don’t be tempted to apply to a wet leaf because the herbicide can simply run off onto the ground rather than dry and be taken in by the black-grass.

3. Respond to conditions

Still days are at a premium and compromises may be needed to get the right timing. Post-emergence herbicide applications may end up being in windier conditions than you would like. Ideally, a post-emergence herbicide is applied as a fine–medium spray with a flat fan nozzle. However, when it’s a little windier an air inclusion nozzle is a better choice to reduce drift.

4. Boom height

50cm above the ground is the magic number for boom height. Contact acting herbicides need to land on the target which may be a small black-grass plant at only GS13. Any higher than 50cm and the amount of drift increases thereby reducing efficacy. Lower forward speeds (maximum 12 km/h), a well-maintained sprayer boom levelling system and an even soil surface all enable uniform application at the correct rate.

5. Product choice

This season sees Monolith (mesosulfuron + propoxycarbazone) available for the first time. It has a 10% uplift in black-grass control compared to its predecessor Atlantis WG and for farms with brome problems it offers exceptional levels of control of all brome species. Like Atlantis WG, use Monolith with 1 L/Ha of the adjuvant biopower to get the best results.

6. Keep it simple

With heavy spring workloads, tank-mixing is always tempting to save time. Unless it’s completely unavoidable, tank mixes should be simple and focus on one set of targets to maximise efficacy. For Monolith, adding residual protection or a broad-leaved weed product is fine but be cautious with other tank-mixes.


If you have any questions, please contact your local CTM or Tweet @Bayer4CropsUK.

Black-grass control: Everything you need to know

Black-grass is the biggest agronomic challenge facing most UK arable farmers. If you have black-grass, taking steps to reduce the population is key.

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