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Agronomy Support

Arable Update – May 2018


In this Edition:

  • Arable Update Special: Weed Control in Spring Cereals
  • Residual Herbicides
  • Post-Emergence broad-leaved weed control
  • Post-Emergence grass weed control


Arable Update Special: Weed Control in Spring Cereals

Spring cereals tend to sit in two camps so far this year – those drilled before the Easter deluge and those that have either only just been drilled or are still to be drilled! Weed control may not be top of mind in these crops with the backlog of work, however, we hope that the quick guide below gives some useful food for thought.

Residual Herbicides

The use of residuals in spring cereals is increasingly popular, primarily driven by the need for grass weed control. There is a strong geographical variance, ranging from 5% of the crop treated with a residual in some areas, to 80% in others. Whatever the products used, efficacy depends upon a number of aligning factors, such as seedbed conditions, appropriate moisture levels, weed seed germination profile, product rate, etc. Results from trials, and feedback from many agronomists, show that a number of important weeds can come through a residual herbicide, such as poppy, fat hen, black bindweed and fumitory. This means that the use of a follow-up contact spray after the use of a residual is commonplace. Products containing Arylex are well suited as follow-up sprays.

Those that drilled spring cereals before Easter were unable to get back to spray and now weeds have passed growth stages where residuals are effective. The more recently sown cereals are moving so fast in the ideal growing conditions, resulting in both crop and weeds going beyond the optimum timing. This means that contact herbicides such as Arylex products will be the main weed control approach for many spring cereal crops.

Post-emergence broad-leaved weed control

Where a residual has not been used, controlling the broad-leaved weeds early is a priority. Data from 38 trials in spring barley, where no residual had been used, showed yield increases from herbicides being greatest when applied between GS12 and 25 of the crop, while applications from GS24-32 did not yield significantly higher than the untreated. Yield however is not the only component to consider as many weeds can impact on harvesting. It is also important to consider weed emergence patterns as post-emergence weed control depends on the weeds being present at the time of application.

The tools available for broad-leaved weed control in spring cereals have changed in recent years with the most significant being the loss of the Ioxynil. At the same time new herbicide introductions have given new tools with many advantages. The addition of the ArylexTM range of herbicides (PixxaroTM, ZyparTM and TrezacTM) offer a number of benefits:

  • Wide spectrum of weeds controlled including fumitory, fat hen and black bindweed
  • Reliable control in variable weather conditions
  • Tank mix compatibility
  • Wide windows of application
  • Low carry-over risk to following crops
  • Control of ALS resistant weeds including poppy and chickweed

Using the products successfully will depend on knowing the weeds present and mixing with other herbicides to fill gaps:

The ideal target size of weeds is from 4-6 leaves. Dose rates of the Arylex products should be adjusted according to weed size and should not be used as a ‘rescue treatment’ when weeds have passed certain weed sizes/growth stages. See product details for more information.

Pixxaro and Trezac often benefit from adding an adjuvant, particularly in conditions where weeds have become waxy.

*Where ALS resistant poppies are present at a high population, every percentage-point of control is critical and in these situations, Trezac is the product of choice.

Post-Emergence grass weed control

In spring barley, post emergence grass weed control is principally based around Axial (Pinoxaden) for wild oats. Applications typically take place at flag leaf emergence of the barley. Zypar, Pixxaro and Trezac are fully supported in a tank mix with Axial plus adjuvant.

In spring wheat, we now have approval for Broadway®Star (at 200g/ha), which delivers control of a wide range of broad-leaved weeds as well as activity on wild oats. The timing of application is between growth stages 23 and 32 of the spring wheat. For more information our tech sheet has details.

For more information click on the links below:




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

Use plant protection products safely.  Always read the label and product information before use.
Pay attention to the Risk Indication and follow the Safety Precautions on the 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.

Pixxaro contains halauxifen-methyl (Arylex active) and fluroxypyr
Trezac contains halauxifen-methyl (Arylex active) and aminopyralid
Zypar contains halauxifen-methyl (Arylex active) and florasulam
Broadway Star contains pyroxsulam and florasulam
Starane Hi-Load contains fluroxypyr

More information can be found at

Corteva AgriScience, Agriculture Division of DowDuPont, CPC2, Capital Park, Fulbourn, Cambridge, CB21 5XE.  Tel: +44 (0) 1462 457272.
Technical Hotline: 0800 689 8899 | |

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Grassland and Maize Agronomy Update – September 2018

Grassland & Maize newsletter

September 2018

For a print-friendly version of this newsletter click here

Welcome to the autumn edition of Grassland and Maize Agronomy, this will be the final newsletter for 2018. Following the merger of Dow AgroSciences, DuPont Crop Protection and DuPont Pioneer, this newsletter now covers maize as well as all things grassland.

These regular technical notes are a seasonal commentary to help those interested in improving grassland and forage productivity on dairy, beef, sheep and equestrian enterprises.

You can claim two CPD points for subscribing to this email update. To subscribe to this newsletter please click here


  • Autumn weed control
  • Buttercup control in autumn
  • Dock control in autumn
  • Low drift nozzles
  • New sown leys – Envy
  • Spray certification
  • Maize silage inoculants
  • Grassland app – new features
  • Anticipated label changes to Forefront T
  • Level 2 Award Safe Use of Pesticides Replacing Grandfather Rights
  • Grassland BASIS
  • FAQs

Autumn weed control


docksAutumn can offer an excellent opportunity for farmers to lessen the weed burden for the following spring, which can help with farm workload and ease herbicide timings, especially where grass is going to be shut up for silage and hay. The wet start to last spring, followed by the dry summer means that some grassland weed control opportunities have been missed, so autumn is an ideal time to catch up. Autumn weed control will be effective as long as the weed is biologically active – so before first frosts appear.



Buttercup control in autumn


Buttercups with EnvyButtercups are common in fields with poor stands of grass, and overgrazing can increase buttercup populations. Buttercup control is traditionally carried out in spring. However, there is usually a wider window for controlling them in early autumn and because flowering has finished control levels can be optimised. Use Envy™ at 2.0 L / ha in 200 litres of water.


Dock control in autumn


Docks which have gone to seed will need topping or cutting before spraying. Spraying dock regrowth with DoxstarPro® or Forefront T® three to four weeks after the last silage cut is a good option. Forefront T is for use on fields grazed by cattle and sheep, but it can also be applied after the last silage / hay cut is taken. If silage or hay is produced from this field the following calendar year, all forage must stay on the farm, along with any manure. The latest a product like DoxstarPro will work effectively is three weeks before the first frost.



Low drift technology


Spray nozzlesMany livestock farmers are still applying herbicides using flat fan nozzles. The use of air inclusion nozzles should be encouraged to reduce spray drift and to enable lower water volumes to be used whilst still maintaining technical performance. Fewer spray tank fills means greater productivity. See our short instructional video for more information



Weed control in autumn new sown leys


new sown leyThere is likely to be a lot of reseeding this autumn as the drought has highlighted the worst performing fields, often with old and shallow-rooted grass species. Investing in a reseed is not cheap and young leys deserve the best start in life to fulfil their yield potential next year. Tackling grassland weeds early improves sward palatability, productivity and reduces costs.

Chickweed and docks can easily out-compete young grass. Controlling two-leaf seedling docks in re-seeds is much easier than tackling large plants with extensive roots the following spring, so take the chance to get rid of them now.

Control weed seedlings in new swards using Envy, which can be sprayed until the end of November. Envy outperforms straight fluroxypyr in fluctuating autumn temperatures but where frosts are predicted then ensure the application is made at least 14 days before cold weather sets in. If this is not feasible wait and apply the following spring. Apply Envy at 1.5 L/ha in 200 L of water once the grass has three true leaves.


Maize silage inoculant


maize silageMicrobial activity can lead to silage heating. Maize is more prone to heating because it is contaminated with more yeast. 11C33 is a new combination silage inoculant specifically designed for treating maize silage. 11C33 contains powerful lactic acid producing strains of bacteria, proprietary to Pioneer, which are specifically chosen because of their ability to convert the types of sugars found in maize to lactic acid. 11C33 also contains the proven strain of Lactobacillus buchneri that significantly improves the aerobic stability of any higher dry matter silage. 11C33 has been specifically developed for treating whole plant forage maize and will improve both aerobic stability and the feeding value of maize silage.




Grassland app – new features


grassland app decision tree screenThe stewardship function of the Dow Grassland App now sends a reminder email if a farmer client does not respond to the initial Forefront T stewardship agreement.

In the latest update of the Dow Grassland App (iOS version) the Decision Tree tool now has a reset button.





Anticipated label changes to Forefront T


Due to changes in the aminopyralid EU approval, changes are anticipated to the Forefront T label, coming in to effect in 2019.

Key changes will be to the application window

  • Do not use between 31st July and 1st March
  • For applications made between 1st March and 31st May, one application may be made per calendar year
  • For applications made between 1st June and 31st July, only one application may be made in a two year period

End of ‘Level 2 Award Safe Use of Pesticides Replacing Grandfather Rights’ – Are you qualified to use pesticides?


Grandfather Rights BookletFarmers who previously sprayed under the ‘Grandfather Rights’ exemption, have until the end of 2018 to take the “City & Guilds Level 2 Award Safe Use of Pesticides Replacing Grandfather Rights”. This qualification will not be available for registration after 31 December 2018. After this date candidates will have to take full qualifications from the PA suite of specified certificates.

This certificate is ideal for those farmers who were born before 31 December 1964 and have many years’ experience in working with professional pesticide products but as yet have not taken a specified certificate.  It was developed on the premise that candidates have had previous training and experience to operate under Grandfather Rights, so takes less time and costs less to register than the full pesticide awards. Candidates can either self-study using a work book or attend a training course to ensure they have the necessary skills and knowledge.  Candidates will have to take a one-to-one practical assessment covering knowledge and competence based on the equipment that they use to apply pesticides.

It is only applicable for those using professional pesticide products on land they own or occupy. For those who want to contract spray or spray for a neighbour using professional products they will need to take the full relevant pesticide qualifications:

Level 2 Principles of Safe Handling and Application of Pesticides (PA1), plus an additional application qualification, e.g.
– Level 2 Award in the Safe Application of Pesticides using Pedestrian Hand Held Equipment (PA6)
– Level 2 Award in the Safe Application of Pesticides Using Self Propelled, Mounted, Trailed Horizontal Boom Sprayers (PA2)

To find out more go and click on qualifications.

BASIS Certificate in Crop Protection (Grassland & Forage Crops)


BASIS logoThis course provides training and certification for sellers of agrochemicals and those giving advice on their use in grassland. It is ideal for those focused on the livestock sector and enables advisors to give bespoke advice to farmers seeking support.

Visit BASIS: to find out when and where the courses are being run in 2018-19.

For more information on courses in Scotland see, or phone Martin Richards 0131 535 4081 or email Moyra Farquhar




Q: When does a new sown ley become an established ley?
A: A new sown ley is grassland under 12 months old. Once a ley has been growing for 12 months it is classified as established grass.

Q: I am thinking of establishing a new grass ley, but concerned about damage from leatherjackets?
A: This autumn could be an ideal time to establish a new ley as leatherjacket numbers are likely to be low due to the recent drought.

Q: Should I treat ragwort this autumn or wait until next spring?
A: The drought conditions over the summer will have caused ragwort plants to create more wax across the leaf surfaces, making it hard for sprays to work effectively. It is better to leave untreated this autumn and spray plants at the rosette stage next spring. If topping to control ragwort this autumn, bear in mind that chopped and wilted ragwort becomes more attractive and palatable to livestock, but is poisonous and can cause liver problems. Keep all animals out of the field until any plant residues have decayed or been removed.

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

For further information please contact the Technical Hotline on 0800 689 8899 / or go to

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 DowDuPont or Pioneer.  All other brand names are trademarks of other manufacturers for which proprietary rights may exist.

DoxstarPro contains fluroxypyr and triclopyr
Envy contains fluroxypyr and florasulam
Forefront T contains aminopyralid and triclopyr

Corteva AgriScience, Agriculture Division of DowDuPont, CPC2, Capital Park, Fulbourn, Cambridge, CB21 5XE.  Tel: +44 (0) 1462 457272.

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View All Topic Sheets
Will DoxstarPro, Forefront T or Pas·Tor control large flowering docks?

No. They must be topped and allowed to regrow. Treatments should then be made under good growing conditions to actively growing plants when they reach the rosette stage.

What pests will Reldan 22 control?

Reldan 22 will control all major mite and insect pests of stored grain including: – Copra mite, Common flour mite*, Cosmopolitan food mite, Saw-toothed grain beetle*, Rust-red grain beetle, Foreign grain beetle, Rust-red flour beetle*, Confused flour beetle, Merchant grain beetle, Indian meal moth, Warehouse moth, Mediterranean flour moth, Grain weevil, Rice weevil
* OP resistant strains exist

Can the straw from oilseed rape treated with ASTROKerb be used for animal bedding?

Oilseed rape straw from crops treated with ASTROKerb needs to remain in the field and must not be baled and used for bedding.  It may be removed from the field to be used for burning for heat or elctricity production.

Can I plant cover crops even where they are not listed as a following crop on the label?

The planting of any crop (not subject to human consumption/MRL requirements) not specifically  recommended on the label would need to be at the users risk where following crop safety has not been demonstrated.

How do you apply Reldan 22 to stores?

Apply using a knapsack sprayer or tractor operated spray lance.

What is the knapsack rate for DoxstarPro, Forefront T, Pas·Tor and Thistlex?

These products are not recommended for application through a knapsack. GrazonPro at 60 ml in 10 litres of water is the best product for spot treatment.

Will any Dow AgroSciences product control ragwort in horse paddocks?

No Dow AgroSciences product is recommended for control of ragwort in horse paddocks. The best method of control is to dig them up. 2,4-D can be used as an overall spray.

What products do Dow AgroSciences recommend to control brambles in grassland?

Brambles should be sprayed between June and August, when plants are actively growing, but before plants begin to senesce in the autumn.

It is essential that all foliage is thoroughly wetted or incomplete kill may result. The maximum concentration must not exceed 60ml of GrazonPro per 10 litres of water.  

Blaster Pro can be used to control brambles in amenity grass.

Do Dow AgroSciences have any herbicides for grassland for use in a weed wiper?

No. Dow AgroSciences’ grassland herbicides have approvals for tractor mounted boom sprayers (Pas·Tor, DoxstarPro, Thistlex, Forefront T) or for application by hand-held equipment such as a knapsack (Grazon Pro). We have no approvals or recommendations for use of products in a weed wiper.