Welcome to the Grassland Agronomy Update from Dow AgroSciences.
These technical notes offer seasonal commentary for those interested in improving grassland productivity and use on dairy, beef, sheep and equestrian enterprises.
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- Treat docks after first-cut
- DoxstarPro, PastorPro or Forefront T – which one for killing docks?
- Full-dose or split-dose?
- How much are weeds costing? Use the Grassland Weed App to find outFocus on Ragwort
- Dow AgroSciences’ show dates
The early spray application window on many farms was missed this year due to the slow start of spring growth but spraying a couple of weeks after first-cut is an excellent opportunity to get on top of dock populations.
Docks in silage crops may not have been large enough – dinner plate sized, to spray in April. Translocated herbicides such as DoxstarPro® need a minimum of three weeks to get right down into the roots to give thorough control.
Spraying two weeks after first-cut will catch the weeds with fresh green leaves and all at a similar growth stage, which is ideal.
There will also not be much grass growth around the weeds, so it is easier to hit the target plants when spraying. This means less water may be needed – so for DoxstarPro this could drop from 400 litres down to 300 litres, making the job quicker but just as effective in terms of killing the weeds.
DoxstarPro, PastorPro or Forefront T – which one for killing docks?
DoxstarPro, PastorPro® and Forefront® T all kill docks, so which one is best to use?
These three translocated products contain different active ingredients and kill a different spectrum of weeds.
|Active ingredients||Fluroxypyr + triclopyr||Clopyralid + fluroxypyr + triclopyr||Aminopyralid + triclopyr|
|Maximum annual dose rate||2 litres/ha||4 litres/ha||2 litres/ha|
|Use area||Grazing & silage ground||Grazing and silage ground||Grazing ground grazed by cattle or sheep and silage ground but only after the last cut|
|Manure/forage movement restrictions||No||No||Yes|
|Water volume||300-400 litres/ha||200-400 litres/ha||200-300 litres/ha|
|Other key weeds controlled||Daisy
|Approximate on farm service price/ha (full rate)||£46-£51||£70-£77||£65-£72|
DoxstarPro is ideal for killing docks in silage crops, as there are no residue issues with manures from animals eating the conserved forage. It has a narrow target weed spectrum, but does a great job on docks. It is a good value option where these weeds are the main problem.
PastorPro is more expensive, but the clopyralid element means it kills nettles and thistles as well as docks. It can be used on silage crops and permanent pasture that is grazed by livestock.
Forefront T delivers the highest levels of control of docks, thistles, nettles, buttercups and dandelions and is excellent on ragwort. It does have restrictions and cannot be used on grass to be cut for silage or hay, except after the final cut of the season.
Forefront T is the product to choose to fight long-established docks and thistle beds, where the root mass underground could be considerable.
Forefront T has to be recommended by an agronomist before a farmer can buy it.
All three products are selective for broadleaved weeds and are very grass safe.
Full-dose or split-dose?
DoxstarPro and PastorPro can be applied as one full dose rate or in a programme as two split rates for the treatment of docks. So what’s best to recommend for use?
DoxstarPro can be applied once during the season at 2 litres/ha and PastorPro once at 4 litres/ha, or they can be split into two treatments of half these rates – typically spring followed by an autumn application
This should be the default recommendation. It delivers the best chance of success and robust weed control – especially where the follow up split rate is unlikely to be applied (work load, travelling conditions etc.)
Where a contractor is being used a single application rate may also be preferred.
Go with a split rate programme when:
- The cutting interval (time between spraying and cutting) is less than 3 weeks – a single split dose treatment will be sufficient to significantly reduce the dock leaf material in cut grass and ensure quality but may limit the scope for lasting control
- Where there are large populations of dock and potential for a shading effect
- Where docks are small and not yet well established
- Where the grass sward is poor and not very competitive – further weed germination is likely so a second spray in the autumn could be appropriate
In tricky situations the success of treatment relies on having everything absolutely right at spraying. Using full rate helps guarantee the best results.
The Dow AgroSciences’ Grassland Weeds app shows how many extra animals could be grazing, how many more litres of milk could be produced, or how many extra tonnes of grass Dry Matter (DM) could be grown, if docks or thistles were controlled.
Many livestock farmers are focused on cutting costs in this current environment of low output prices. Getting more grassland from what they’ve got can help them save money. Where weeds limit grassland productivity the gain in terms of extra grass far outweighs the cost of treatment and given that grass is the cheapest form of feed significant cost saving can be generated. The Dow Grassland APP’s Weed Cost feature models easy to input values and generates scenarios to see how controlling perennial weeds can affect productivity.
Level of docks 20%
Target yield (t DM/ha) 11
Grass quality (MJ ME) 11.5
Field size 5 ha
46 extra sheep could be grazing
4 extra beef cattle could be grazing
11,934 extra litres of milk could be produced from the extra grass
11 extra tonnes of grass dry matter
(Model assumes 50% utilisation)
If you haven’t already downloaded the Dow Grassland APP you can do so with these links:
Focus on Ragwort
Ragwort is a danger to livestock, particularly if eaten when it is dying. Recently wording on herbicide labels has changed to make sure farmers take all precautions to prevent this happening.
Common ragwort is a tall biennial yellow flowered plant often seen on roadside verges and poorly managed livestock paddocks.
In its second year, it starts off with a rosette of young leaves, but then grows to 1.5 meters with bright yellow flowers from June to October. Viable seeds are produced from August to September and generally establish close to the mother plant.
Ragwort contains 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 permeate throughout the entire clamp, affecting a whole herd of cows.
Where 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.
Removal of all wilted plants after treatment is essential, or all animals should be kept out of the field for at least four to five weeks, giving time for all the ragwort foliage to rot.
Eighteen months ago, the Chemicals Research Directorate (CRD) decided to strengthen the wording on herbicide labels for products being used against ragwort. This is because the wilting process, particularly after spraying with herbicide, increases the soluble sugar content of the foliage, making it even more attractive.
In future labels will read in the DIRECTIONS FOR USE:
Exclude livestock during treatment and do not allow livestock to graze treated grassland for at least [xx] days following treatment. Where ragwort is present users should consult the Code of Practice on How to Prevent the Spread of Ragwort. Ragwort plants sprayed with this herbicide are more palatable with higher levels of toxins. Animals should be excluded from treated areas until any ragwort has completely recovered or died and there is no visual sign of the dead weed. Do not include treated ragwort in hay or silage crops.
What is the preferred method of managing Forefront T stewardship reporting? APP or Pad or CropWalker / Gatekeeper spray recs?
The Dow Grassland APP has been configured to manage Forefront T stewardship obligations. It is quick and easy to use, does not require any paperwork and automatically creates the required reports for managing this effort. This is the preferred method for all. The APP is available in all 3 formats: IOS, Android & Windows.
Where the APP cannot be used, agronomists should send an email to firstname.lastname@example.org to opt out for 2016 and their reason. They will need to continue to use the pad or spray recs as an alternative though. In 2017 the plan is that only the APP will be used.
What effect will our products have on Cow parsley?
GrazonPro® or Forefront will give moderate control (75 to 85%) and Pastor Pro will give some control but less than 75%.
How long do I wait to stitch clover back into the sward after an application of Forefront T?
If just grass is being over seeded, wait 4 weeks. If clover is also being over seeded, wait 4 months.
Which of Dow AgroSciences’ range can be applied through a weedwiper?
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.
Which of Dow AgroSciences’ range can be applied to new sown leys?
Our grassland product range cannot be used on new sown leys (grassland less than 1 year old) currently – even GrazonPro. The best solution for broadleaved weed control where clover is not present is Starane® Hi-Load.
Will DoxstarPro control dandelions?
Yes, its not a label weed but you can expect good control (greater than 85%) pre-flowering or post flowering (assuming good leaf area). When flowering, levels of control may be less.
How soon can chickens be put back in a field where spot treatment with GrazonPro has taken place?
If stock enter a field before 7 days then remove immediately. There should be no health concerns but monitor stock closely and if you have a concern notify your vet. Pets (dogs) and people should not enter the field until the spray is thoroughly dry.
The technical team from Dow AgroSciences will be out and about at many shows and events this summer.
|June||1st||NSA Scot Sheep||West Linton, Peebleshire|
|June||7th||NSA South Sheep||Salisbury|
|June||9th||Royal Welsh Grassland Event||Corwen|
|July||6-7th||Livestock Event||Birmingham NEC|