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Agronomy Support

Agronomy Update – 10 September 2014

In this Edition

Which pre-emergence for grassweeds in winter wheat?
Complete the programme to control weeds in grassland.
Reduce winter N losses from FYM, biosolids or digestate.

This Edition’s FAQs:  
Does Dow AgroSciences have anything for Cabbage Stem Flea Beetle in rape?
What do you think about Centurion Max in Oilseed Rape grassweed programmes?
Can I use Galera this autumn?

Dates for the diary

Which pre-emergence for grassweeds in winter wheat?

Drilling cereals Mundford Norfolk2 - 9-11-12Farmers recognise the integration of cultural and chemical programmes is vital to keep the menace of grassweeds in wheat in check.

At least 97% control of blackgrass is required to prevent populations increasing. Ryegrass too is becoming more difficult to control chemically and sterile brome can compete and grow very quickly, so here too a pre-emergence as part of the integrated programme can help achieve higher levels of control and avoid increasing weed burden.


Blackgrass Ryegrass Sterile Brome*
1st choice  240g/ha flufenacet applied pre-emergence
e.g. Liberator 0.6 L/ha, Crystal 4.0 L/ha. Additional actives may be stacked.
Prosulfocarb e.g. Defy 4.0-5.0 L/ha
+/-Stomp Aqua 1.75 L/ha
Flufenacet + PDM
e.g. Crystal 4.0 L/ha
Alternative choice See above PDM e.g. Stomp Aqua 3.5 L/ha
or Flufenacet based e.g. Crystal 4.0 L/ha
or Liberator 0.6 L/ha or Vigon 1.0 L/ha
e.g. Stomp Aqua 2.6 L/ha

*2000g PDM required overall in the brome programme
PDM & Stomp Aqua can be interchanged for PicoPro

Follow up post-emergence with UNITE® (blackgrass and early bromes) and Broadway® Star (bromes, ryegrass) at the 1-3 leaf stage of the grassweed when actively growing.

Take some tips on beating blackgrass.

Complete the programme to control weeds in grassland.

Sequences of DoxstarPRO® or Pastor® are supported for dock control by Dow AgroSciences.

If you have used half-rate DoxstarPRO (1.0 L/ha) or Pastor (2.0 L/ha) earlier this year, do remember to top-up with the remaining half dose to give the best chance of good weed control. Treating docks 2-3 weeks post-cut is ideal as docks will have fresh, even re-growth which is readily receptive to spraying.  Docks are best treated at the rosette stage.

Treatment is best made when docks are actively growing (but for Pastor must be completed by 31st Ocober).  Apply with a water volume of 300 L/ha. If weed numbers are high or if the sward is dense, increase to 400 L/ha.

Reduce winter N losses from FYM, biosolids or digestate.

Many farmers apply FYM, biosolids or digestate to stubbles in the autumn. These are valuable sources of nitrogen but is liable to loss over the winter.  Crops on light sandy/leachy soils are most at risk of loss.

N-Lock™ can help maintain this nitrogen over winter.  Applying N-Lock just before muck application will inhibit conversion of ammonium to nitrate. When applied when soil temperatures are declining ( and below 15°C), N-Lock will reduce nitrogen lossses from nitrification by 50% through the late autumn and winter months.

Incorporate manure and N-Lock within 10 days of N-Lock application. N-Lock may be mixed with glyphosate.

This edition’s FAQs:

Does Dow AgroSciences have anything for Cabbage Stem Flea Beetle in rape?

We are very aware this autumn, without neo-nic seed treatments, growers and agronomists are very concerned about crop damage but on this occasion, Dow AgroSciences are not able to provide a pest solution.

What do you think about Centurion Max in Oilseed Rape grassweed programmes?

Applications of Centurion Max should be made in October followed, at least 14 days later, by Kerb® Flo 500 or ASTROKerb® in November. This approach maximises the opportunity to achieve the best blackgrass control and minimises the possibility of negative crop effects. Independent trials established in autumn 2013 proved how effective a programme of Centurion Max followed by Kerb Flo 500 or ASTROKerb can be in controlling high levels of blackgrass in oilseed rape crops.

Can I use Galera this autumn?

Galera® (MAPP 11961) can be used this autumn. All farm stocks need to be used by final approval date 30th September 2015.  (Please note, Dow AgroSciences will cease selling Galera, MAPP 11961, on 30th September 2014. It can be sold by distribution until 31st January 2015).

Next year, Dow AgroSciences will be selling re-registered Galera (MAPP 16413) which can only be used from 1st March  and will have no autumn approval.

Dates for the diary

 If you have questions or queries relating to any of our products or would like to speak to one of us face to face, come and visit us at your local event.

Nov 19th AgriScot, Ingliston
Nov 19th-20th Croptec, Peterborough


For more regular updates on agronomic issues, find us on Twitter and Facebook!

If you require any further information please contact our technical Hotline on 0800 689 8899 or your local Dow AgroSciences representative.

More information can be found at uk.dowagro.com

Use plant protection products safely. Always read the label and product information before use. For further information including warning phrases and symbols refer to label.

® Trademark of the Dow Chemical Company (“Dow”) or an affiliated company of Dow. All other brand names are trademarks of other manufacturers for which proprietary rights may exist.

ASTROKerb contains aminopyralid and propyzamide
Broadway Star contains pyroxsulam and florasulam
DoxstarPRO contains fluroxypyr and triclopyr
Galera contains clopyralid and picloram
Kerb Flo 500 contains propyzamide
Pastor contains clopyralid, fluroxypyr and triclopyr
UNITE contains pyroxsulam and flupyrsulfuron-methyl-sodium
N-Lock is a novel micro-encapsulated form of nitrapyrin

Dow AgroSciences Limited, Latchmore Court, Brand Street, Hitchin, Hertfordshire, SG5 1NH.Tel: +44 (0) 1462 457272. Technical Hotline: 0800 689 8899 | UKHotline@dow.com | uk.dowagro.com


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Grassweed Emergence Monitor will resume again in the Autumn


Plan Your Blackgrass/Grassweed Management

A crucial step to achieving successful control of headache grassweeds in winter wheat – blackgrass, ryegrasses and sterile brome, is to monitor when grassweeds emerge, so that post-emergence treatments can be applied as soon as possible when the weeds are small and are actively growing.

To help growers and advisers understand growth of these weeds, Dow AgroSciences is funding an ADAS monitoring scheme once again this season.

If you would like to receive the latest GEM report directly to your inbox or would like to find out more about this service, please contact our Technical Hotline on 0800 689 8899, your local Dow AgroSciences representative or E-mail – ukhotline@dow.com.

Related Links

      Print                                broadway-star      broadway-sunrise

GEM first began in the autumn of 2010, and already some key factors influencing emergence patterns have been recognised – the rapid emergence of sterile brome being one of them. Sterile brome is most effectively controlled in the autumn when small.

This year we are focusing on blackgrass and monitoring two sites in Cambridgeshire and Oxfordshire.

Report 9 – 14th March 2014

Dow AgroSciences’ Grassweed Emergence Monitor (GEM) in conjunction with ADAS is focusing on monitoring blackgrass emergence in two key blackgrass areas of the UK – Cambridgeshire and Oxfordshire. Winter wheat has been drilled in September and late October and includes blackgrass sown at 500 seeds/m2 and a “natural” unsown blackgrass population.

It is important to remember that germination of grassweeds will also be subject to local factors and the information provided by GEM should supplement but not replace field monitoring.

This week’s report:

There has been no further emergence at either site for either drilling date.

Established blackgrass is growing. Blackgrass growth stages vary between two leaves with the largest plants approaching GS30 in the September drilled.

15.03.14 Cambridgeshire early drilled 15.03.14 Oxfordshire early drilled
15.03.14 Cambridgeshire late drilled 15.03.14 Oxfordshire late drilled

All sown grassweeds are drilled at 500/m2. No herbicide treatment applied.

Current Advice for Grassweed Control in Winter Wheat:

Apply UNITE® + adjuvant ASAP. UNITE may be used up to GS 24 of the blackgrass. Consider including additional residual e.g. 120g ai/ha flufenacet particularly where no pre-em has been applied, or where further emergence of grassweeds is expected e.g. spring bromes.

For the best results with UNITE and Broadway Star, 2-3 days of active growth are required on either side of the application.

Apply UNITE at 0.27 kg/ha (1 pack treats 4 has) in 100-200 litres water/ha (Optimum 130-150 litres water/ha) as a fine – medium spray with flat-fan or twin fluid nozzles to a drying leaf. UNITE is rainfast in 2 hours.

Use UNITE where blackgrass is the driver-weed.

Use Broadway® Star where bromes, ryegrass, wild oats and are the driver-weeds.



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Leatherjacket Report – Autumn Update 30th September 2014

crows and rooksRecent reports of adult crane-flies in Central England and Northern Ireland mean growers need to be alert for damage. Earlier this spring the SRUC reported numbers in the soil at the highest recorded levels in 39 years.

Adult crane-flies lay eggs July-September particularly on grassland or in “grassy” stubbles. Hatched leatherjackets are vulnerable to desiccation especially when young, however the rainfall forecast next week may aid their survival. Growers should be alert for any damage particularly on newly established cereals and grass leys.

Leatherjacket Damage Thresholds

 >0.3-0.5 million/ha (30-50/m2) Damage likely in new ley or cereal
 >0.5-0.6 million/ha (50-60/m2) Autumn population in grassland likely to cause damage in following cereals.
 >1 million/ha (100/m2) Population in permanent grass where treatment likely to give economic benefit.
 >2 million/ha (200/m2) Population in permanent grass likely to show visible damage if untreated.


crows and rooks

Crows and rooks feeding on larvae

leatherjacket larvae

Leatherjacket larvae


Fields with a history of leatherjacket damage should be monitored for large numbers of rooks and crows feeding on the larvae. Risk assessments and testing for the presence of leatherjacket larvae will provide a good indication of fields that are most likely to need treatment.

For cereals applications may be made from post-drilling.

Find out more about controlling leatherjackets in grassland and cereals.

If treatment is justified use Equity® at 1.5 L/ha applied in 200 to 1000 litres of water/ha.

If using Dursban® WG at the recommended rate is 1.0 Kg/ha applied in 200 to 1000 litres of water/ha.

Be aware control will be reduced if soil temperatures are below 5°C or soils are dry as the larvae will move deeper into the soil profile.

Use low drift nozzles and extend buffer zones to preserve Dursban WG and Equity use.

For conventional boom sprayer:

  • Use LERAP – low drift – three star nozzles
  • AND adopt a 20 metre no-spray buffer zone (1 metre for dry water bodies)

Say No to Drift




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Kerb Weather Data

Get the full picture and weather data

To get more detailed information, starting in October,  sign up for our e-newsletter and full weather data to see whether conditions are correct for Kerb® Flo 500 or ASTROKerb® applications.

Using Kerb Flo 500 or ASTROKerb gives you the highest possible control of blackgrass and other difficult to control grassweeds, important not only for the rape crop but also reducing the weed seed burden in following cereal crops. ASTROKerb also provides excellent control of poppy and mayweed.

Follow these guidelines to get the best possible control of blackgrass in your fields from Kerb Flo 500 and ASTROKerb:

  • Performance is best where crops have been established using min-till techniques
  • Applications should be made to firm, moist soils with a fine tilth
  • Applications must be made to small blackgrass plants, before they tiller
  • Best applied when soil temperatures have got down to 10°C at 30 cm and falling and there is sufficient moisture in the soil for plant uptake. Both these conditions are rarely met before November. (Both products can be used up to January 31st). Please note the soil temperature in the postcode search is at 10 cm and will be more variable than at 30 cm
  • Increased rates should be used where blackgrass resistance has been confirmed
  • Strategic use is recommended in tank mix or sequence with graminicides. In difficult blackgrass situations  adding a “ dim” with good blackgrass activity to the Kerb Flo 500 or ASTROKerb nearly always improves control.
    Alternatively independent trials  have proven how effective a programme of Centurion Max followed by Kerb Flo 500 or ASTROKerb can be in controlling high levels of blackgrass in oilseed rape crops. Applications of Centurion Max should be made in October followed, at least 14 days later, by Kerb Flo 500 or ASTROKerb in November.


Good stewardship

Water stewardship needs to be top of mind to both safeguard the environment and to protect these valuable products from withdrawal. If you can travel, applications of Kerb Flo 500 or ASTROKerb must only be made after taking all necessary precautions to avoid contaminating surface waters. Kerb Flo 500 and ASTROKerb may be applied in frosty conditions but avoid application onto frozen ground where subsequent rainfall could result in run-off into watercourses. More information on water stewardship can be found on the Voluntary Initiative website.


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