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Arable Update – October 2018

Arable Update

In this Edition

  •  Autumn residuals essential to get the best from and protect spring herbicides
  • Kerb Weather Data Tool

Autumn residuals essential to get the best from and protect spring herbicides

Whether your challenge is ryegrass, brome or poppy, using a residual herbicide in autumn is an essential part of a weed control strategy – to both achieve high levels of control and prevent weed resistance occurring.

Trials work by Corteva Agriscience™, over a number of years, has shown that for control of sterile brome the use of the residual Crystal (Pendimethalin + Flufenacet), applied either pre-emergence or peri-emergence of the winter wheat, followed by Broadway® Star (in autumn or spring) consistently gave outstanding control. Similar results have been obtained for ryegrass control with the use of Prosulfocarb (Defy) as a residual herbicide followed by Broadway Star. Alex Nichols, Cereal Herbicide Product Manager points out “The reason we see better results with Broadway Star applications when used in a programme is principally due to the fact that the residual herbicide either completely takes out or heavily retarding the growth of some of the early emerging grassweeds, this then means that when the contact herbicide Broadway Star is applied (often in the spring) it is dealing with smaller, later emerging weeds. Trying to control a sterile brome plant that germinated with or soon after the crop, would, in the spring, leave a plant that is far too big to be controlled effectively by a selective herbicide. It is also important to note that residual herbicides can also have their performance impaired by poor seed beds and dry conditions”.

The use of a programme is also a key mechanism for reducing the risk of resistance developing. Alex Nichols remarks “Using different modes of action is a well understood tactic for avoiding the development of weed resistance. It stands to reason that by using a programme you put yourself in a position of achieving very high (99%+) levels of control and significantly reducing seed return. Whereas without a programme it is likely that more weeds would survive the application due to being too big for effective control and increasing the number of surviving plants and weed return which will increase the risk of resistance developing.”

Sterile brome control

It’s not only grassweeds that need consideration, broad-leaved weed control in winter cereals can benefit from a programme with residual herbicides.

“Relying on spring applied contact broad-leaved weed herbicides alone is a recipe for problems – weeds will be either too big for effective control and the probability of resistance developing will be high.”

In situations where ALS resistant poppy is present on the farm, using Stomp Aqua (pendimethalin) in the autumn is a key way of getting control of the large flush of weeds that follows drilling, this can then be followed by application of Zypar™ in the spring, targeting weeds at the 4-6 leaf stage.

Kerb Weather Data Tool

KWDCorteva Agriscience agriculture division of DowDuPont have updated and refreshed the Kerb Weather Data (KWD) tool on our website (available from mid-October).

New for 2018, the refreshed tool not only provides old favourites such as a postcode soil temperatures and moisture, but also rainfall and wind predictions that help growers and advisors plan their spraying workload but a new national soil temperature summary.

This tool is meant to be used as a guide to local weather conditions to aid growers and advisors make tactical decisions to optimize their ASTROKerb® and Kerb® Flo activity against blackgrass.

If you use ASTROKerb or Kerb Flo 500 when the traffic light is on red, soil temperatures may be too high, propyzamide will breakdown quickly and blackgrass control may be compromised.

In forward crops, large canopies may be closing in rows before the KWD tool indicates green for go. Dow AgroSciences trials over a number of years have shown blackgrass control from propyzamide is not impeded by large crop canopies.

Always adhere to stewardship guidelines especially with respect to water, help ensure we keep essential active ingredients in our armoury to help grow our crops.

If you require any further information please contact our Technical Hotline on 0800 689 8899 or your local Corteva Agriscience 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 DowDuPont or Pioneer.  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
Kerb Flo 500 contains propyzamide
Zypar contains Arylex and florasulam

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

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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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Kerb Weather Data – Final Report – week ending 30 November 2018

Welcome to the final edition for this autumn, providing timing guidance for propyzamide applications to oilseed rape.

Soil temperatures (at 30cm) have cooled and applications are now being made. With falling temperatures and conditions still good to travel at the moment we are entering an ideal period of time for applications to be made.  Consider applications when conditions allow. When applying propyzamide it is important to consider water stewardship, and that when applications are made users are taking all precautions to avoid water contamination. Both Kerb Flo 500 and ASTROKerb can be used until 31st January.

It is important to wait until soil temperatures have cooled to less than 10°C as this optimises the blackgrass control activity from your propyzamide application. Cooler soil temperatures slow propyzamide breakdown and ensures blackgrass roots are exposed to propyzamide for longer periods of time, thus optimizing control.

Use the maps and links below to find the data for soil temperatures and moisture-deficits in your region.  Please note at 30 cm soil temperature reading is less variable than the more commonly used 10 cm reading.

Kerb Weather Map week ending 30 November 2018

Whilst conditions in most regions across the UK appear to be green i.e. ready for application of Kerb® (or ASTROKerb®), please check your local status using the postcode checker for a more accurate reading.

For optimal blackgrass control Corteva Agriscience recommend Kerb Flo 500 and ASTROKerb applications are made when soil temperatures are 10°C and falling, and there is sufficient soil moisture in the soil for grassweed uptake. Both these criteria are usually met from the first week in November.

Check out application conditions for your local postcode



Click on the link to the left to use the postcode checker.

Simply enter your postcode in the banner and click GO to view the results.









Please ensure good practice when using Kerb Flo 500 or ASTROKerb to avoid restrictions on these products


Will large crop canopies interfere with blackgrass control?

Trials have shown that even where canopies are dense, excellent blackgrass control can be achieved once optimum soil conditions are met.

As ASTROKerb will mainly be used for blackgrass, this should drive application timing. ASTROKerb has both contact and root activity on poppies and mayweeds and in our extensive trials programme, when optimally timed for blackgrass control even where canopies were large, control of these broad-leaved weeds has been good. Where broad-leaved weeds are the sole driver an earlier application could be considered before broad-leaved weeds become too large.

Can I apply Kerb Flo 500 in a frost?

Kerb Flo 500 may be applied in frosty conditions but avoid application onto frozen ground where subsequent rainfall could result in run-off into watercourses.

For ASTROKerb please ensure frost is off the target broad-leaved weed.

Do I need a dry-leaf for application?

The propyzamide active in Kerb Flo 500 is soil-acting so spraying wet weeds at run-off or light rainfall after application is not an issue. Ideally, the rainfastness of ASTROKerb is 1 hour for the aminopyralid element. Spraying on a drying leaf is OK but if rainfall falls within 1 hour and causes run-off efficacy may be reduced. All applications should be made with due regard to water stewardship, i.e. do not spray where there is a risk of run-off to adjacent watercourses.

Should I be worried spraying small, backward rape?

Crop selectivity for propyzamide is by depth protection of the roots.  Applications to very small oilseed rape plants can cause problems such as stunted growth with leaves fused to the axil or stem and yield depression. Once a crop has reached the three true leaf stage the roots are at sufficient depth to not take up a dose of propyzamide that could cause problems. Some judgement may be needed in backward crops as to the risk on any smaller plants and on shallow rooted areas. Applications of Kerb Flo 500 and ASTROKerb may be made to 31st January.

 What can I add to the Kerb programme to improve blackgrass control?

With high populations of blackgrass the use of programmes to give control is increasingly vital. Adding a “fop or dim” with good blackgrass activity as a sequence or tank-mix in the programme nearly always improves control and is frequently better than carbetamide/propyzamide programmes.

Download Topic Sheet 16 “Advice for Blackgrass Control in Oilseed Rape” for further advice.


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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.