• Grassland – Still Time to Get on Top of Those Thistles
• Controlling Obscure Grassland Weeds
• Update on Sugar Beet Weed Management with Dow Shield 400
• Early Weed Control in Forage Maize
• Wheat Blossom midge – Defend Your Crop with Close Monitoring
• On the Road – Cereals 2012
• Dow AgroSciences Funded Research into Herbicide Resistance
• This Edition’s FAQs:
  • Can I still use Timbrel?
  • Where can I find information about product rainfastness?
  • What controls Hogweed in grassland?
  • Where can I find the latest information of tank mix partners?

The wet May weather may have pushed back first and second cuts, so there is still time for weed control to maximise yields, forage palatability and profits. The period between first and second cut is the ideal time to control key yield damaging weeds as both weeds and grass are growing at their maximum rate. Most commonly creeping thistle and spear thistle are endemic in older grasslands and grazing pastures. Careful attention should be given to grazing pastures, as poaching by livestock may encourage a flush of weeds. Controlling thistles will not only improve palatability but is good practice on farms where Orf in sheep is endemic as a precautionary measure.

Thistlex* can be used in leys more than 12 months old for the control of creeping thistle and spear thistle. Management of perennial weeds will not only reward this season’s yields, but because Thistlex is translocated to the roots, it offers longer term control. Alternative  “phenoxy” based products will mainly control top-growth so despite  appearing fast acting, they are not as effective at killing the root systems. The same is true of cutting. A single well timed application of Thistlex at 1.0 L/ha in 200-400 L/ha of water will control both creeping thistle and spear thistle populations.  In addition, Thistlex also controls dandelions and has some effect on common nettle.  The best time to treat is when the weeds are at the rosette stage and actively growing. After first cut has been taken, allow 2-3 weeks of re-growth before applying Thistlex. Like all products in the Dow AgroSciences grassland portfolio, Thistlex is extremely safe to grass and will not check growth or compromise yield.

For grazing pastures and in regions where aminopyralid use is permitted, Forefront* or Forefront T can be used for the control of docks, thistles, nettles, creeping buttercup, dandelion, ragwort and chickweed. As well as a superb weed spectrum, Forefront/Forefront T can be used at a reduced water volume of 200 L/ha. The use of Forefront and Forefront T is only permitted where product stewardship policies are enforced with restrictions in manure and forage management.

  

There are a wide range of additional weeds that are encountered in grassland. Where we have some knowledge of how our product might affect such weeds we have detailed this below. This in no way constitutes a recommendation of use but merely serves to give some indication of the effect of our products on those weeds.

For the latest in season support literature, click on the product you would like to learn more about:

Sugar beet crop development is generally slow due to the weather so there is still time to use Dow Shield^# 400 against a number of key annual and perennial weed species. A maximum total dose of 0.75 L/ha of Dow Shield 400 can be applied to a beet crop, with a maximum individual dose of 0.5 L/ha. 

A single application of Dow Shield 400 at 0.25 L/ha will control annual weeds including mayweed, groundsel, corn marigold and smooth sow-thistles at the two true leaf stage. When used alone, applications of Dow Shield 400 can begin once the smallest crop plants have expanded cotyledons. If Dow Shield 400 is applied in a programme with other herbicides, the first true leaves on crop plants must be at least 10mm long.  Inclusion of Dow Shield 400 in a programme improves activity on many weeds, such as corn marigold, groundsel, fools parsley, mayweeds and black bindweed.

For optimal control against perennials including creeping thistle and spear thistle, Dow Shield 400 should be used in a sequence at 0.25 L/ha when the weed is at the rosette stage followed by a second application at 0.5 L/ha 3-4 weeks later. The latest timing for Dow Shield 400 is when the crop meets between the rows (BBCH 39) and applications should be completed before the end of June.

For the control of volunteer potatoes in beet crops, Dow Shield 400 is best used as part of a programme. Include 0.25 L/ha of Dow Shield 400 with applications of ethofumesate and phenmedipham when the potato shoots are between 5-10cm tall and a second application when volunteer shoots are 10-20cm. For extended haulm emergence, a three spray programme of 0.16 L/ha in conjunction with ethofumesate and triflusulfuron-methyl is recommended. The first treatment should be made when the potato haulm is 5 to 10cm high, followed by two further applications at the same rate at fortnightly intervals.

More information on weed control in sugar beet with Dow Shield 400 

This season’s weather may have delayed maize drilling so it’s important to allow for good establishment with a robust herbicide programme. Once maize crops are established they are good competitors, but early post-emergence when weeds are growing fast, maize crops can struggle.

Starane* 2 can be used in forage maize crops from the 3 leaf stage up to the 6 leaf expanded stage. Applications should be made before the crop reaches 20cm and should not be applied once the buttress roots start to develop on the first node as this can interfere with their development. When Starane 2 is used on forage maize, it should not be tank mixed with any other product. Used at the maximum rate of 1.0 L/ha, Starane 2 has label recommendations for the control of black nightshade but will also control cleavers, chickweed, hemp-nettle and forget-me-not and has activity against black bindweed, henbit deadnettle, red dead nettle, fumitory and knotgrass.

Maize growers and agronomists will be relieved to know use of Dow Shield 400 has recently been approved for use on forage maize crops. The new more concentrated Dow Shield 400 product can be applied to all varieties of maize from the three leaf expanded stage (BBCH13) up to and including BBCH19. Used at 0.25 L/ha per crop, Dow Shield 400 can be used to control annual weeds including creeping thistle, sow thistle, mayweed species, groundsel and corn marigold with additional activity on black bindweed, pale persicaria and redshank. As this recommendation does not yet appear on the label, users will be required to possess a Notice of Approval which can be downloaded from the Dow AgroSciences website: Dow Shield 400 Notice of Approval 0646 of 2012 

Wet soils and temperatures above 15°C favour Wheat Blossom midge pupation, a pest which not only damages yield but can reduce grain quality and give rise to secondary fungal attack. Crops this year may be particularly prone to attack if a sudden warm spell kicks off pupation whilst crops are still backwards.

It is the larvae that cause the damage by feeding on the developing grain and crops are most vulnerable at ear emergence (GS 53-59), or slightly earlier for yellow blossom midge (GS 51-55). When adults emerge they live for approximately seven days and lay their eggs usually mid-way through this cycle on the emerging ears. Eggs hatch within 4-10 days and larvae feed on the developing grain within the floret. Once larvae have entered the glume, they are protected from chemical applications so it is important to act quickly when threshold levels are reached. Adults fly predominantly at dusk and this is the best time to monitor levels. When there are one or more adults per six ears in wheat crops intended for milling/seed or one or more adult midge per three ears in wheat crops intended for feed, treatment is advised. Those growing susceptible varieties should be vigilant. 

Dow AgroSciences provide a monitoring service via Pestwatch in collaboration with ADAS, which monitors populations of Wheat Blossom midge as well as other key cereal pests including Wheat Bulb fly, Leatherjackets and Saddle Gall midge. A Pestwatch report for Wheat Blossom midge larvae will be available later this month.

Dursban* WG has label recommendations for control of wheat blossom midge and should be applied at 0.6 kg/ha in 200-1000 L/ha water. One ear application per crop is permitted at this rate up to GS 59. Effects of Dursban WG will persist for 7-10 days post application and will control subsequent flights and emerging larvae. Pyrethroids and other alternatives will only offer reduction of adult midges, are only persistent for two days post-application and will not control larval populations. For optimal control applications of Dursban WG should not be delayed once threshold has been reached.

All major groups of cereal insecticides pose a potential risk to beneficial insects particularly when sprayed during summer and the wheat blossom midge risk period. Precautions should be taken to minimise impact against wildlife by only applying an effective insecticide when necessary. Complying with the SAY NO TO DRIFT guidelines for Dursban WG, including adopting a 20 metre no-spray buffer zone beside watercourses and using LERAP three star low-drift nozzles and adopting a 12 metre no-spray buffer zone beside hedgerows or grass strips will allow an area for beneficial arthropods to survive and re-colonise the field. Natural enemies of cereal pests are an important natural control mechanism.

Differential Effect of Insecticide Groups when Applied in June

Pyrethroids: generalised effects based on Lambda cyhalothrin, Deltamethrin and Taufluvalinate, though there may be some individual differences on some specific beneficial.  Ref. – A Review of the Side Effects of Insecticides Used Against Cereal Pests in the UK (Rothamsted Research)

Come and bowl out your BLACKGRASS at Cereals! - At this year’s Cereals event on 13th and 14th June in Boothby Graffoe, Lincolnshire, we will be unveiling the name of our strongly anticipated blackgrass herbicide. The new product, currently known by its code name GF-2070, is a unique combination of our pyroxsulam molecule with flupyrsulfuron-methyl for control of blackgrass populations in addition to a wide range of grass and broadleaved weeds in winter wheat crops.

On the stand we will be hosting a bowling competition, where each day the winner will receive an iPad!  So come and see us at stand F710 (look out for the red feather flags) and bowl away your blackgrass!
 

As part of Dow AgroSciences commitment to agricultural research, we are funding a PhD student working as part of the weed and ecology management group at the University of Warwick.

Laura Davies is in the first of a four year research project where she hopes to map herbicide resistance in UK blackgrass and Italian ryegrass populations. Her research is focussing on the potential for resistance development and appropriate management strategies. Laura is looking to collect seed samples this summer for analysis and is ideally looking for farmers with good herbicide use history. If you think you are able to assist Laura in her sampling, please contact her at l.davies.1@warwick.ac.uk 

Can I Still use Timbrel?

 

Timbrel* registration continues.  Based on latest communications with CRD, we expect that end users will continue to buy Timbrel through their usual suppliers for most of this year, and can continue to use up any stocks throughout most of 2013 at least.

This is of great benefit for the many operators that use Timbrel for a great diversity of uses, from the control of difficult woody weeds such as Buddleia, brambles, gorse and Japanese Knotweed to the control of Rhododendron ponticum when trying to prevent the spread of the devastating disease Phytopthera ramorum (Sudden Oak Death), that is affecting our nations larch population amongst others.

Where can I find information about product rainfastness?

During unsettled conditions, it is paramount to plan applications around the weather. Rainfast data is based on applications made to a dry leaf. More information about product rainfastness can be found on the Dow AgroSciences website: Rainfastness

What controls Hogweed in grassland?

Common hogweed, Heracleum sphondylium, is a herbaceous perennial commonly found in meadows and pastures. There are no label recommendations for the control of common hogweed although Grazon* 90 has activity against it. For optimal control, applications should be made before flowering when the weed is small and actively growing.

Where can I find the latest information of Tank mix partners?

Our tank mix lists are constantly being updated in correlation with new products entering the market. You can find the most current lists on the Dow AgroSciences website: Tank Mix Summaries.

Subscribing to Dow AgroSciences' Agronomy Update & Pestwatch gives eligibility for 1 Crop Protection BASIS Points annually. Please include course name "Agronomy Update & Pestwatch" and number "CP/19948/1112/g" on your training record. These details apply until 31st May 2012.

For more regular updates on current agronomic issues, find us on Twitter!   

If you require any further information please contact our technical Hotline on 0800 689 8899 or your local Dow AgroSciences representative.

Dow AgroSciences supports the safety and efficacy of its products for tank mixes shown as Physically and Biologically Compatible, but does not warrant the efficacy of other tank mix partners.

Use plant protection products safely.  Always read the label and product information before use.
For further information including warning phrases please refer to the product label.

* Doxstar, Dursban, Forefront, Grazon, Pastor, Starane, Thistlex and Timbrel are trademarks of Dow AgroSciences LLC.
^# Dow Shield is a trademark of the Dow Chemical Company.
All other brand names are trademarks of other manufacturers for which proprietary rights may exist.

Doxstar contains triclopyr and fluroxypyr
Dursban WG contains chlorpyrifos
Dow Shield 400 contains clopyralid
Forefront contains aminopyralid and fluroxypyr
Forefront T contains aminopyralid and triclopyr
GF-2070 contains pyroxsulam and flupyrsulfuron-methyl
Grazon 90 contains clopyralid and triclopyr
Pastor contains triclopyr, fluroxypyr and clopyralid
Starane 2 contains fluroxypyr
Thistlex contains clopyralid and triclopyr
Timbrel contains triclopyr

More info at www.dowagro.com/uk