Your interest:

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 | |

Read the full story

Grassland and Maize Agronomy Update – May 2018

Grassland & Maize newsletter

May 2018

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.


  • Docks post first cut
  • Paddock weed control
  • Thistle species
  • Ragwort control
  • Silage inoculants – aerobic stability
  • Pas·Tor agronomy pack
  • Game cover
  • Woody weeds
  • Farmer spray certification
  • FAQs
  • Grassland shows calendar

Spraying docks after first cut

Docks ready for treating in silage groundThe demand for dock control solutions has really picked up after a slow start. It’s likely that many farmers will want to treat after silage cutting. Spraying a couple of weeks after first-cut is an excellent opportunity to get good levels of control. If spray contractors are used, make sure they are booked in to apply a spray 2-3 weeks after silage cut is taken, as by then dock regrowth should be at the ideal stage for control as the weeds will have fresh green leaves and all be at a similar growth stage (dinner plate sized). There will also not be much grass growth around the weeds, so it is easier to hit the target plants when spraying. Translocated herbicides such as DoxstarPro® need a minimum of three weeks to get right down into the roots to give thorough long term control, so apply in plenty of time before second silage cut is made. Where docks are present, weed control is a small cost relative to the gain in extra grass and silage produced. If cutting takes place earlier e.g. around 14 days, then short term control is unlikely to be affected but the like hood of having to undertake a follow up spray the following year us increased.

Paddock weed controlPaddock

Envy™ –for weeds typically found in pastures which receive minimal nitrogen, controls both creeping and meadow buttercups, daisies and dandelions. Best levels of control are achieved before flowering. If you spray when they are in flower you can still get good control but not to the same level as if sprayed earlier.

These weeds will smother grass and limit the provision of forage to grazing animals. Envy contains florasulam + fluroxypyr, it has no manure management restrictions after use – so ideal to use in pony paddocks. Its short stock withdrawal period of just 7 days makes planning in its use much easier then phenoxy based options which require a 14 day stock withdrawal period.

Thistle Species

ThistlesThere are over 150 species of thistles worldwide, with 20 species growing in the UK. The two most common and damaging are creeping thistle (Cirsium arvense), and spear (or Scotch) thistle (Cirsium vulgare).

Creeping thistle is a perennial that grows from seed or from root sections in the soil. Once established, the root mass can be greater than the plant above ground, competing effectively with the grass.

Spear Thistle is a biennial that grows from seed, and in the first year often goes unnoticed, since it produces only a small rosette. In the second year the plant can grow to over a metre in diameter before flowering, posing a serious economic threat.

Other thistle species include marsh thistle (Cirsium palustre) which is common on damp ground such as marshes, wet fields, moorland and beside streams, and carline thistle (Carlina vulgaris),  a spiny biennial plant with brown flower heads, which can be found on dry, chalk grassland.

Options for spraying thistles

  • Where thistles dominate, spray with Thistlex® using a tractor mounted or self-propelled sprayer. Thistlex also controls nettles.
  • If the area taken by the thistles is less than 5%, spot treat with Grazon®Pro.
  • If a broader range of weeds is involved, use the Pas·Tor® Agronomy Pack.

Ragwort control

RagwortRagwort contains an alkaloid; a cumulative poison, which when grazed over a period of time affects an animal’s liver. Horses need only to eat 4-8% of their bodyweight for it to be fatal. Cattle are more susceptible than sheep, while pigs and chickens are also sensitive. Once cattle and horses have consumed a fatal dose – probably about 3kg of fresh plant material for an adult, there is no known antidote.

Stock will not usually eat ragwort while it is still growing. But when it is cut and wilts it becomes more attractive and palatable. It is a particular problem in fields to be cut for hay or silage, where its toxicity remains and can contaminate the entire clamp.

Where ragwort plant numbers are low and the soil is moist, digging the plants out by hand (wearing gloves) is an option. All the pulled material must be removed from the field before the animals are let back in.

For larger infestations where application is via tractor-mounted or self-propelled sprayer, very high levels of control can be achieved with Forefront T®. This should be done before flowering when the ragwort plants are still at the rosette stage.

Animals should be excluded from treated areas until any ragwort has completely recovered or died and there is no visible sign of the dead weed.  Do not include treated ragwort in hay or silage crops.

Silage inoculants – aerobic stability

Good weather during silaging means that dry matter content will rise rapidly during wilting. Higher dry matter content raises the risk of spoilage due to yeast and mould activity in the silage following air ingress. Lactobacillus buchneri containing silage additives control and modify the fermentation process, resulting in improved aerobic stability of silage at feed-out and a reduction in total fermentation losses in silages prone to heating and spoilage. In order to maximise the improvement in aerobic stability silage should be allowed to ferment for at least 4 weeks prior to opening. Using a Pioneer brand silage additive that contain Lactobacillus buchneri reduces dry matter losses. Pioneer brand silage additives are  non-toxic biological solutions that improve nutritional quality and aerobic stability of high dry matter grass and whole crop cereal silages.


PasTor graphic

Pas·Tor Agronomy Pack reminder

The Pas·Tor agronomy pack now features an improved outer case to make handling easier. Each agronomy pack treats 2 ha. The Pas·Tor agronomy pack is the best solution where there is a mixed weed population of docks, thistles and nettles, and use of Forefront T is not appropriate (silage ground / cost).

Each case contains a 2 litre pack of Pas and a 2 litre pack of Tor. The agronomy pack offers excellent selectivity, and both components have the same LERAP, grazing and cutting intervals.


Weed control in Game Cover Crops

Game coverLate May/early June is the perfect time to control weeds appearing in cereal and brassica game cover crops, which have all germinated and are now growing away.  Weed control in game cover crops can be tricky, as there is usually a mix of desired game cover plants, and potentially a lot of target weeds all growing up together.

Broad spectrum treatments, such as Dow Shield® 400, control a wide range of weeds without harming the game cover species such as kale, maize, millet, miscanthus, phacelia, cereals and stubble turnips. Buckwheat, quinoa and sorghum can suffer some crop damage, but any damage will be slight and certainly the cover crops should recover.

Where thistles are the main problem weed in game cover crops, spraying Thistlex at 1 L/ha will control them well.

A number of Dow AgroSciences products have Extensions of Authorisation for Minor Use (EAMU) approval in game cover. These are:

More information on weed control in game cover can be found in our Game Cover Crops Topic Sheet

Woody weedGorses

June through to August is the ideal time to target woody weeds such as bramble, broom and gorse (whins) with Grazon Pro.

The plants should be sprayed when actively growing, with good leaf cover, and pre-senescence.



Grandfather rights – reminder

C&G NPTCThe certificate in safe use of pesticides replacing grandfather rights will be withdrawn from December 31st 2018. If you have farmer clients – particularly those wishing to use GrazonPro or glyphosate around the farm and that don’t have this qualification or a PA6 then do encourage them to get certified else they will lose the right to apply.


Q. I want to make the Forefront T stewardship recommendation via the Dow Grassland APP but I don’t have a smart phone, what do I do?
A. Use the stewardship feature on the web:

Q. What effect will our products have on Cow parsley?
A. Cow parsley is not a label weed for any of our products, but Grazon Pro or Forefront T will give moderate control (75 to 85%) and Pas·Tor will give some control but less than 75%.

Show dates

The grassland show season is now in full swing. 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.

 May 25th NBA Beef Expo Shrewsbury Livestock Auction Centre
 May 30th NSA Scot Sheep Ballantrae
July 18th NSA Sheep Event Three Counties Showground, Malvern
September 8th NSA South Sheep South of England Showground


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.

Dow Shield 400 contains clopyralid
DoxstarPro contains fluroxypyr and triclopyr
Envy contains fluroxypyr and florasulam
Forefront T contains aminopyralid and triclopyr
GrazonPro contains triclopyr and clopyralid
Kerb Flo contains propyzamide
Pas·Tor Agronomy Pack contains clopyralid, fluroxypyr and triclopyr
Starane Hi-Load HL contains fluroxypyr
Starane XL contains fluroxypyr and florasulam
Thistlex contains clopyralid and triclopyr

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

Read the full story

If you would like paper copies of any of our leaflets please complete this form.

View All Topic Sheets
What are the LERAP requirements for Broadway Star/Palio?

The CRD re-approvals for Broadway Star (MAPP 18273) and Palio (MAPP 18349) removed the requirement for a buffer zone and therefore LERAP requirement for these products. It is however important to check other requirements e.g. Cross Compliance for the Basic Payment Scheme (BPS) requires no application of pesticides to land within 2 metres of the centre of a watercourse or field ditch, or to land from the edge of the watercourse or field ditch to 1 metre on the landward side of the top of the bank of a watercourse or field ditch.

What is the current situation with regard to Unite?

Unite, along with other products that contain flupyrsulfuron, are now subject to a withdrawal notice. The timelines are as follows:

Up until the 31 March 2018 Unite can be sold (sales period)

Up until the 13 December 2018 Unite can be used, stored or disposed of (use-up period)

Full details of the withdrawal notice can be found here

Please note this withdrawal does not affect Broadway Star and Palio

Why is Unite subject to a withdrawal notice?

The active substance, flupyrsulfuron, has not been approved for renewal at an EU level. Note this does not affect Palio and Broadway Star as these products do not contain flupyrsulfuron.

What are the following crop restrictions/cultivation requirements for Pixxaro EC?

After an application of Pixxaro EC at 0.5 L/ha up to BBCH 45, the following crops may be sown.
• Autumn: Beans*, Cereals, Clover*, Grass, Lucerne*, Oilseed Rape, Peas, Phacelia
• Spring: Beans, Cereals, Clover, Grass, Lucerne, Maize, Oilseed rape, Onions, Peas, Potatoes, Sugar beet, Sunflowers

*Plough prior to sowing

The Pixxaro EC label advises ploughing prior to sowing winter beans, however, Dow AgroSciences support autumn sown field beans without ploughing prior to drilling, following an application of Pixxaro EC (in spring to the previous cereal crop) with one exception: high pH soil (8 or over) in a dry summer, in these situations ploughing is then recommended prior to drilling autumn sown field beans.
We are working on adding following crops such as carrots, brassica transplants and borage as a following crop.

When is the best time to control sterile brome in winter wheat?

Sterile or barren brome germinates in the autumn and grows very quickly.

Control is best achieved in a programme with  2000g ai/ha pendimethalin followed ideally by autumn applied Broadway Star or Unite. Best control is achieved when applied before GS24 of the brome.  

Which pre-emergence herbicide should I use for ryegrass control in a Broadway Star programme?

Use 3200 g  ai / Ha of prosulfocarb.  Additional pendimethalin may help.

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.

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.