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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 – July 2018

Grassland & Maize newsletter

July 2018

For a print version of this newsletter click here

Welcome to the Grassland and Maize Agronomy Update from DowDuPont. With 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.


  • Thistles in established grass
  • ‘Fire brigade’ treatments
  • Invasive weeds
  • Rejuvenation with Forefront T
  • Forefront T Stewardship via the app
  • Paddocks
  • The Decision Tree tool on the app
  • New grass leys
  • FAQs
  • Grassland shows calendar

Thistles in established grass

creeping thistlesCreeping thistle thrived in the wet summer last year and the consequences are being seen this year. With many thistles now being a metre high or more and starting to flower, now is a good time to tackle them before they set and spread their seed.

Tall, flowering thistles need to be cut down first, as they are too big and not at the right vegetative stage to be sprayed with translocated herbicides. Then left for three weeks to regrow, the fresh leaves will be big enough to provide the ideal target for a spray.

Where thistles are the main problem, Thistlex® is the best product to use. If there is a broader range of weeds involved, then Pas·Tor Agronomy Pack is a good option. Alternatively use Forefront® T in grazing only situations or after the last hay or silage cut. If the population of thistles is less than 5%, spot treatment with Grazon®Pro is more cost effective.

All of these products will offer excellent control of all species of thistles (including spear, creeping and marsh). By controlling thistles now, the area of grass available to stock this year will increase (reduced ‘shadow’ effect), the number of new plants germinating from seed this year can be reduced and the level of weeds present in the grass next spring can also be reduced.

Topping thistles gives only temporary reprieve, especially with creeping thistles as they produce more stems from buds running below ground after cutting.

Docks treated with Forefront T‘Fire Brigade’ Treatments

 In an ideal world, all weed control would be carried out in a timely manner. However, in reality other jobs such as caring for livestock, or unsuitable weather conditions at the correct timing for weed control, means that weeds get out of hand, and remedial action is needed. Where weeds have grown past the ideal vegetative growth stage and are in the process of flowering, application of herbicides at this timing will result in reduced levels of control. The best course of action is to top them (this re-energises perennial weeds to resume vegetative growth), allow them to regrow for approximately three weeks and then spray the leafy regrowth.

Invasive weeds

BramblesA land occupier has a responsibility to prevent invasive non-native plants on their land from spreading into the wild, and to prevent them from spreading on to a neighbour’s property.

Invasive non-native plants are species which have been introduced to the UK that have the ability to outcompete our native flora. Species such as Japanese knotweed, Himalayan balsam and giant hogweed are listed under schedule 9 to the Wildlife and Countryside Act 1981. Under the Environmental Protection Act 1980, Japanese knotweed and giant hogweed are classified as controlled waste.

Invasive weeds native to the UK include ragwort, gorse and bramble.

For further information on controlling native and non-native invasive weeds see our Invasive Weed Control Leaflet.

Pasture Rejuvenation with Forefront T

Forefront T is a unique herbicide giving lasting control of all major grassland broad-leaved weeds. Forefront T can transform a weedy ley into a productive pasture allowing grass species to win through. When coupled with over seeding then permanent pastures can be rejuvenated, giving them a longer life.

Clover can be drilled four months after application

Forefront T can be used on silage fields AFTER the last cut of silage has been taken.

Before application of Forefront T After application of Forefront T

If a field, cut for hay or silage is treated with Forefront T, sufficient herbicide residue remains in the grass which when eaten and passed out by the animal can, if the manure is used on sensitive crops, cause some damage. This is why the label use is for grazing ground only. Ensuring the end user knows this reduces the risk that third parties might be affected.

Forefront T stewardship via the Dow Grassland App

grassland appAll Forefront T stewardship recommendations are now recorded via the Dow Grassland App as the paper stewardship pads are no longer in use.

To use the app for stewardship, register on the app as an advisor. You will need to be BASIS qualified and have completed Forefront T stewardship training. If you are an agronomist and you wish to receive Stewardship training, please contact your local representative, or the technical hotline on 0800 6898899.

For those Agronomists who are already suitably trained, but who have not yet used the Grassland App for Stewardship reasons, here is a helpful reminder of what you need to do

  • Click on the Stewardship button
  • Click on the + symbol in the top right of the screen to add the farmer client details
  • Once their details have been added, save to return to your Agronomist Client Portal
  • Click on the farmer’s name
  • Enter the area (in hectares) to be sprayed in the white box
  • Click send to send the stewardship to the farmer
  • The farmer receives a Forefront T Stewardship Guidelines email from the email address
  • To acknowledge, the farmer clicks on the link in the email
  • NB: to prompt the agronomist’s version of the app to update the farmer’s status from ‘pending’ to ‘accepted’ after the email has been accepted, you may need to swipe to close the app, and then reopen
  • Once the farmer has accepted, an email is sent to the farmer, the agronomist, and the distributor if applicable, enabling the Forefront T to be released to the farmer

The Dow Grassland App is available free for iOS, android and as a web version for use on a pc.


pony paddockHorse paddocks often become overrun with weeds, meaning there is less grass for the animals to eat and the field can look messy. While horses relish mixed swards to graze, weeds such as buttercups, docks, dandelions, daisies and plantains limit the amount of grass available.

Spraying fields with a product such as Envy™ offers a quick and easy fix. Any manure subsequently produced from treated paddocks will be free of herbicide residues and can be used in gardens or on allotments.

While Envy is rainfast in only two hours, horses do need to be taken out of the field for seven days after treatment* – which is a lot less time than for many herbicides.

*In the absence of ragwort

If paddock owners want to apply herbicide with a knapsack sprayer, around fence-lines or gates, GrazonPro is one of a limited number of products that can be applied using this method. It gives excellent control of docks, thistles, nettles and also brambles, gorse and broom.

As Envy and GrazonPro are classed as Professional Use Pesticides. This means they can be bought by anyone, but can only be applied by people who have completed a relevant City and Guilds/National Proficiency Test Council (NPTC) course.

Most paddock owners will contract out their spraying to local certified farmers or contractors. To help find one visit or use the find a spray contractor feature in the support tools section of the Dow Grassland App.

The decision tree tool on the app

 The latest iOS version of the Dow Grassland App now contains a decision tree. Android and web-based versions will be updated shortly. The decision tree tool gives users more options to find the best solution. Users can select the primary weed problem, plus a secondary weed if required, whether grass is newly sown or established, the size of weeds present, the spray application method that will be used, and the grass usage, ie grazing or cutting. The app then finds the best solutions for that particular scenario.

New grass leys

weedy new sown leyMany new leys were sown late this year. Some will need spraying now to control the weeds that are competing with the young grass. Leystar™ and Envy, both newly registered last year are amongst the few products to have approval for weed control in new sown leys.

Leystar can be used up to 31st August and Envy up to 30th November.

With no chemical control options now available for reducing frit fly and leather jacket populations, careful planning to establish an autumn sown ley is required now.

Leave as much time as possible between destroying the previous grass crop and sowing the new one to reduce the threat from frit fly and leather jackets.


Q: What is the best herbicide to use to control brambles?

A: Brambles should be sprayed between June and August, when plants are actively growing, but before plants begin to die back 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.

Q: Will any Dow AgroSciences product control ragwort in horse paddocks?

A: 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.

Show dates

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.

July 18th NSA Sheep Event Three Counties Showground, Malvern
September 8th NSA South Sheep South of England Showground

Please visit us on our new award-winning stand. We look forward to seeing you.

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.

Envy contains fluroxypyr and florasulam
Forefront T contains aminopyralid and triclopyr
GrazonPro contains triclopyr and clopyralid
Leystar contains fluroxypyr, florasulam and clopyralid
Pas·Tor Agronomy Pack contains clopyralid, fluroxypyr and triclopyr
Thistlex contains clopyralid 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.