Agronomy Update – 30 March 2015

In this Edition

Remind me of latest timings for Galera

Save time by tank-mixing fungicides and herbicides!

Leatherjackets and spring drillings

What should you be doing now about weeds in grazing areas and silage crops?


This Edition’s FAQ:
– What is the best product for getting rid of chickweed in gappy leys?

Remind me of latest timings for Galera

Galera TimingThe latest application timing for Galera® in winter oilseed rape, flower-buds visible above the crop canopy, is linked to the physiological development stage of the crop and is not associated with the number of leaves present around the flower-buds that are forming.

Recent pigeon grazing will have left some crops stripped of their leaves; therefore assessing timings for Galera applications could be difficult. This growth stage timing is not dependent upon leaves protecting the developing flower-buds as there is no requirement for a physical barrier to protect the buds from Galera.

Dow Shield® 400 has a similar cut-off timing.

Save time by tank-mixing fungicides and herbicides!

Early season wheat fungicides are upon us with more reliance on early protection against Septoria. There are many gSprayingrass and broad-leaved weeds needing to be controlled as well before they compete with the crop. Growth regulators are an added pressure. Taking advantage of the tank-mixability of UNITE® and Broadway® Star is great for saving time.

Each spray application costs between £10/ha (farmer applied) and £14/ha (contractor applied) and saving a pass can add up to big money and avoid hassle this spring, as well as improve yield through better timeliness.

Broadway Star and UNITE are supported with chlorothalonil and this will not compromise efficacy and performance on weeds. These will also mix with many formulated fungicides such as Cherokee, Alto Elite, Tracker and Ignite +/- Bravo 500. Avoid mixing with products containing tebuconazole as these can give excessive shortening.

Do not add a PGR on top of this mix. If using a PGR stick with UNITE or Broadway Star + adjuvant + ½ rate chlormequat and nothing else.

Remember both Broadway Star and UNITE offer control of a huge range of broad-leaved weeds such as cleavers, cranesbill, poppy, speedwell, charlock, groundsel, volunteer rape, volunteer beet and many others as well as grassweeds, further cutting down on need for additional passes or products.

Always use an adjuvant with either Broadway Star or UNITE.

Remember to follow tank cleaning procedure on label when using UNITE or Broadway Star!

Leatherjackets and spring drillings

Newly sown spring cereals as well as root crops are particularly susceptible to damage from leatherjackets.

Pest numbers go in cycles and leatherjackets have been abundant over the last couple of years. However initial results from the SRUC autumn survey, suggests the risk is lower this year. Leatherjackets can be assessed by soil sampling with corers and washing out in a laboratory, or by heating soil cores and driving out the leatherjackets. An alternative method is based on driving plastic pipes into the ground and filling with brine and counting leatherjackets that float to the surface. For row crops numbers can be assessed by scratching either side of the row.

Damage thresholds for treatment:

>0.25 million/ha (25/m2)
Or 5 per 2 metres of row
Damage likely in sugar beet and other row crops.
>0.3-0.5 million/ha (30-50/m2)
Or 3-5 per metre of row
Damage likely in new ley or cereal
>1 million/ha (100/m2)Population in permanent grass where treatment likely to give economic benefit.
>2 million/ha (200/m2)Population in permanent grass likely to show visible damage if untreated.

By May, larvae will stop feeding and pupate into adults.

What should you be doing now about weeds in grazing areas and silage crops?

  • Reflect on last year – which fields/areas will benefit most from weed control this year?
  • Walk the fields now and map where seedling docks and thistles have overwintered.
  • Decide whether these areas warrant spraying. Remember where weeds grow grass cannot grow. A 10% infestation of docks or thistles means 10% less grass.
  • Select products that translocate within the stem, leaves and roots of the target weed, giving long-lasting control. Choose a herbicide that has been specifically formulated for the target weed, e.g. Doxstar®Pro for docks and Thistlex® for thistles.
  • Book the contractor if required.  Demand for grassland spraying is increasing due to changes in the application regulations.  Select a spray date when the weeds are actively growing and 20cm high or across (docks) or 25cm high or across (thistles). In silage crops, spraying should take place three to four weeks before harvest – work back on a calendar to find the ideal date.

Grass Docks and Dairy GrazingDocks

  • Grow in soils rich in nitrogen and phosphates
  • Colonise trampled/poached grass
  • Can also appear as seedlings in arable crops after grass
  • Left untreated infestations increase in size
  • Tap roots can reach depths of 1.5m where they access moisture and nutrients
  • Flower from June onwards
  • Can produce 60,000 ripe seeds/year
  • Seeds spread on animals or in manure
  • 60% the feed value of grass
  • Tough stalks can puncture silage wrap on round bales leading to spoilage
  • Can live ten years or more
  • Crowns can fragment over time so one plant can become many.

This edition’s FAQ:

What is the best product for getting rid of chickweed in gappy leys?

DoxstarPro and Forefront® T are very good at getting rid of chickweed in established silage and grazing leys respectively – but they must be at least one year old.

A new herbicide from Dow AgroSciences is planned. Currently in the approval process with The Chemicals Regulations Directorate (CRD), the new product should be available for farmers to use in Spring 2016.


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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.

Broadway Star contains pyroxsulam and florasulam
Dow Shield 400 contains clopyralid
DoxstarPro contains fluroxypyr and triclopyr

Forefront T contains aminopyralid and triclopyr
Galera contains clopyralid and picloram
Thistlex contains clopyralid and triclopyr
UNITE contains pyroxsulam and flupyrsulfuron-methyl

More information can be found at

Dow AgroSciences Limited, Latchmore Court, Brand Street, Hitchin, Hertfordshire, SG5 1NH.Tel: +44 (0) 1462 457272. Technical Hotline: 0800 689 8899 | |


Pastor gets the ‘Pro’ treatment

PastorPro bottleDow AgroSciences is introducing a new, improved formulation of its broad-spectrum herbicide Pastor called Pastor®Pro. It will join Doxstar®Pro and Grazon®Pro in the company’s portfolio of grassland products.

A wealth of specialist crops for classic herbicide

OnionsVegetable, allium and nursery crop growers have been plagued in the last few years by the loss of crop protection actives, either as more products are revoked or go through re-registration and lose crops. But one manufacturer has been busy adding to their recommendations and supporting and encouraging Extension of Authorisation for Minor Uses (EAMU’s) for their chemistry. “We get a lot of queries from growers on our Hotline about what they can use on their vegetables and onion crops. One of our classic active ingredients clopyralid continues to be an important herbicide for these specialist growers and each year additional crops are added or recommendations altered to make them even better,” says Dilwyn Harris, Principal Biologist for Dow AgroSciences.

Tackle buttercups in grass before they flower

Spray buttercups when they are green and actively growing for best control

Spray buttercups when they are green and actively growing for best control

The mild winter and kind spring weather means many soils in the south and west have now reached 5-6°C at 10cm depth. This has triggered both grass and broad-leaved weed growth and the competition for light, space and nutrients is under way.

“As day length increases, every day soil temperatures reach 5oC or more, root and shoot growth starts,” says Andy Bailey, grassland specialist for Dow AgroSciences. “Soil processes also start to kick in as bacteria start to break down organic matter producing nitrogen in plant-available form, which also helps stimulate new growth.

“However, weeds do not start all growing at the same time. Buttercups and dandelions are the first to get going. Bad infestations may need spraying with a translocated herbicide in the next two to three weeks, when rosettes of actively growing, fresh green leaves can be seen,” Mr. Bailey advises.

2.It is too late to treat buttercups when they are flowering and the field is yellow

It is too late to treat buttercups when they are flowering and the field is yellow

“Waiting until the field is a carpet of yellow in April is too late and spraying then will be less effective. If docks are also a problem, farmers should not be tempted to spray for both at the same time – when the docks are at the ideal stage for treating, buttercups and dandelions will be too far advanced.

“Broad-spectrum herbicides such as Pastor on silage ground and Forefront T on land grazed by cattle and sheep, are good options for early applications to catch both buttercups and dandelions.”

Other weeds

Ragwort will be the next weed to start growing, followed by docks and thistles.

“In the South West, docks are just bursting into life, with new leaves springing out of the centre of established plants and seedling docks pushing up through the sward. But it is likely to be another month before they are ready for spraying – by then they should be at the rosette stage and at least 25cm across or high.”

Last chance saloon for effective grassweed control

Blackgrass_001With winter wheat crops growing away quickly and variable weather windows for spraying, it is the last chance for growers to complete grassweed programmes, before both weeds and crops pass optimal growth stages, says Dow AgroSciences.