Grassland and Maize Agronomy Update – April 2018

Grassland & Maize newsletter

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.

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  • Curled dock versus broad leaved dock
  • Treating docks ahead of first cut silage
  • Why multi-strain grass silage inoculants can help your grass silage fermentation
  • Timing of Ragwort control
  • Weedwiper and use of Dow AgroSciences selective herbicides
  • Weed spectrum of Leystar
  • What control you can expect when targeting flowering buttercup
  • Dandelions in grazing fields
  • Sycamore seedlings in paddocks
  • Grandfather rights – reminder
  • Labels and use on grassland
  • FAQs
  • Grassland shows calendar

Curled dock versus broad-leaved dock

Broad-leaved dock (Rumex obtusifolius) and curled dock (Rumex crispus) are problem weeds in grassland.

Broad-leaved dock has broad lower leaves with an elongated heart shape.  The leaves are usually at least half as wide as they are long.  The flowering stems are well branched.   Flowering starts in late June or July and the fruits, when fully ripe, are a reddish-brown colour and often remain in clusters on the stems.

Curled dock has narrower leaves which are usually at least three times long as wide.  The leaf margins are often wavy.  The flowering stems are much less branched that those of broad-leaved dock and tend to be carried close to the main stem.  Flowering starts in early June.

Although both species are perennials, curled dock tends to be much shorter-lived than broad-leaved dock, and can behave as an annual or biennial in some situations with plants dying after flowering.  Individual plants of broad-leaved dock can be very long-lived, especially in pastures.  Both species occur in meadows and pastures.  Both species produce large numbers of seeds (>25,000 per plant) which are very persistent in the soil.

Check product labels when selecting a dock herbicide. Some products such as Cimarron and Pinnacle only have broad-leaved docks on the label.


Broad-leaved dock                                                                      Curled dock

Advantages of treating docks ahead of first cut silage

Spraying docks with a translocated herbicide now, when they are young, healthy and actively growing, will increase grass silage yields and improve the feed quality of the resulting forage. The higher dry matter and sugar content of grass after controlling docks is also likely to improve silage fermentation and reduce the chances of making poor silage.

Docks are at the right size for spraying when they are 20 cm wide rosette or “dinner-plate sized.”

The best way to tackle docks in silage crops is to spray with Doxstar®Pro, which enters the plant and travels right down to the roots. It takes three to four weeks to do this, so farmers should work out when first cut is likely to take place, then spray at least three weeks before that date.


Why the multi-strain grass silage inoculants, Pioneer Brand 1188 and Pioneer Brand 11G22, can help your grass silage fermentation

If the weather is unfavourable during harvest then the grass crop will be wetter and will undergo a more extensive fermentation. At low dry matter contents fermentation stability may not be reached until the pH is as low as 3.8. Strains of bacteria demonstrate varying levels of tolerance across the likely range of pH values.

Dry and sunny weather before and during silage harvest will increase sugar levels. As the dry matter increases so does the osmotic pressure. Different strains of bacteria demonstrate varying ability to withstand changes in osmotic pressures.    Strains that have a higher osmotolerance should perform better in high dry matter silages. Silage inoculants with more than one strain of bacteria are more likely to be effective across a wide range of moisture contents.

Strains of Lactobacillus plantarum show poor tolerance at the higher pH levels that are associated with the early stage of the silage fermentation. Entercoccus strains are more active at higher pH levels and it is for this reason that two strains of Entercoccus are contained within Pioneer Brand 1188 and Pioneer Brand 11G22 silage inoculants. Their role is to “kick-start” the fermentation until the pH drops to 5.0 when the Lactobacillus plantarum become more active.

Inoculants reduce dry matter losses from silage even under favourable weather conditions. Extensive trials comparing the fermentation dry matter losses under difficult, medium and easy ensiling conditions show that the application of an inoculant significantly reduces dry matter losses even under easy conditions.


Benefits of using Pioneer Brand 1188 and Pioneer Brand 11G22:

  • Rapidly lowers pH and stabilises the silage with minimal use of available sugars
  • The controlled fermentation results in 20% less in-silo losses
  • Reduces ammonia nitrogen, content by an average 46%
  • Maximises lactic acid production, minimises acetic and butyric acid formation
  • Improving nutritional value of treated silage: An average advantage of 3.5 units of DMD
  • Increasing silage intakes with both cattle and sheep by 5-16%
  • Increasing the rumen microbial protein by 50% due to higher energy and protein quality in treated silage
  • Producing an extra 1.5 Kg milk/day
  • Producing an extra 4 Kg beef live – weight gain per tonne of grass ensiled

These results have been proven in independent research trials

Timing of Ragwort control

Ragwort is one of the most frequent causes of plant poisoning of livestock. It is responsible for over 90% of the complaints on injurious weeds in the United Kingdom.

Cultural control of ragwort by cutting, digging out or puling is often ineffective. Chemical control with MCPA and 2,4-D gives some control on young plants but performs poorly on late rosettes or flowering plants. The best long term control of ragwort is achieved from Forefront® T applied to actively growing rosettes.

Dow AgroSciences trials – ragwort control one year after treatment

Weedwiper and use of Dow AgroSciences selective herbicides

Weedwiper is not an approved application technique for any of our products. The only product that has an approval today via this method is glyphosate.

CRD require a full regulatory dossier for this method of application and so consequently this is something we cannot support at this time.

Weed spectrum of Leystar and its use as a new sown ley herbicide

In new grass leys the key target weeds are annual weeds such as mayweed, chickweed, fat-hen, seedling thistles etc. Leystar™ controls these seedling weeds and many more besides. Many grassland herbicides have lost their approval for new sown leys, so Leystar fills a vital gap. Leystar is applied at 1.0 L/ha to new sown leys, and can be used from when the grass has three true leaves.

    Seedling weeds controlled with Leystar at 1.0 L/ha
Black bindweed Common sorrell Field bindweed Mayweed (1 true leaf)
Black nightshade Corn chamomile Fool’s parsley Ribwort plantain
 Buttercup Corn marigold Forget-me-not Shepherd’s-purse
 Charlock (1 true leaf)  Daisy Greater plantain Spurrey
Chickweed Dandelion Groundsel Thistles (from seed) (1 true leaf)
 Cleavers (1 true leaf) Docks Hemp-nettle Wild Radish
 Cover, trefoil Fat-hen(up to 2 leaf)  Knotgrass Yarrow


What control you can expect when targeting flowering buttercup

Best control of buttercups is achieved if they are sprayed before flowering. However, the trigger for spraying a field of buttercups is often once the farmer has noticed that the field has turned a shade of buttercup yellow! Replicated Dow AgroSciences trials showed that useful control of creeping buttercup can still be obtained during flowering. However, for best overall control, pre-flowering applications of Envy™ or Forefront T both at 2.0 L/ha are preferred.




Dandelions in grazing fields

The ubiquitous dandelion is found throughout the country, in grassland where there is limited disturbance. Although dandelions are palatable to stock, they are relatively unproductive in terms of nutrition and so can reduce the overall value of pasture if allowed to establish. Envy at 2.0 L/ha is a good option for dandelion control. It’s an ideal product in horse paddocks too as there are no manure restrictions.





Sycamore seedlings in paddocks

A common query at this time of year is how to control sycamore seedlings, particularly in horse paddocks. Ingestion of sycamore seedlings containing the toxin hypoglycin A can cause the sometimes fatal condition equine atypical myopathy in horses and ponies. Although not a label recommendation, spot treatment with Grazon®Pro or a boom spray with DoxstarPro or the Pas·Tor agronomy pack will give control of sycamore seedlings. Horse owners need to be aware of grazing intervals, as may need to leave longer than 7 days if poisonous weeds are present.



Grandfather rights – reminder

This option will no longer be available 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.

Labels and use on grassland

Make sure only herbicides that have a label recommendation for use on grassland are used on this crop. If it’s not on the label then farmers are being miss-sold, have no backup from the manufacturer if something goes wrong and it can be an illegal application putting in jeopardy cross compliance.


Q. Are sprays safe to the grass?

A. Dow AgroSciences selective herbicides only work on broad-leaved weeds and do not affect any species of grass. This means they are completely safe to use in grass fields when used correctly. However, clover will be severely damaged or destroyed.

Q. When can silage be cut if Forefront T is going to be used this spring?

A. Forefront T should NOT be used on grass destined for silage in the year of its application. It can be used in a silage field after the last cut of silage has been taken. Grass from that field can be used to make silage the following year but resulting silage and manure must stay on the farm.

Show dates

May 10th Grassland UK Bath & West Showground
May 16th Royal Welsh Grassland Carnbwll, Powys
 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


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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.

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DoxstarPro contains fluroxypyr and triclopyr
GrazonPro contains clopyralid and triclopyr
Envy contains fluroxypyr and florasulam
Forefront T contains aminopyralid and triclopyr
Leystar contains fluroxypyr, clopyralid and florasulam
Pas·Tor contains clopyralid, fluroxypyr and triclopyr

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

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