Tell me more about Saddle Gall Midge 

Using Broadway Star to control wild oats 

What weeds does Spitfire control? 

PERENNIAL WEEDS - control options in grassland 

This edition's FAQs:

- Are Florasulam and Pyroxsulam SUs? 

- What does frost damage in WOSR look like? 

- Mildew is around. How do I use Fortress to control it? 

We are already receiving enquiries about Saddle Gall Midge – Haplodiplosis marginata – including what growers might be able to do about it in their crops.

Agronomists are reporting finding considerable numbers of  bright reddy-orange larvae and cocoons in the soil in Buckinghamshire, Cambridgeshire and Suffolk, often where they had problems last year.

In affected wheat crops last year, it is reported that yields were depressed by as much as 1.0 t/ha overall, and by considerably more in badly affected parts of fields. Wheat, barley, rye and, to a lesser extent, oats, can all be affected. Most reports of damage last year were in wheat crops. Crop damage is most typically seen in the internode below the developing ear. This part of the stem becomes swollen, remains short and is easily broken. Affected ears remain within the sheath and grain fill is compromised. The highest levels of damage are often found around field edges. Wet spring weather seems to increase adult numbers.

Adult midges are up to 5.0 mm long with distinctive reddy-brown colouring. Each female can lay 200 eggs, which take 7 days to develop at temperatures of 18°C. Larvae also grow to about 5.0 mm and have an orange-red body colouring.

The Saddle Gall Midge life cycle includes one generation per year, with adult midges being most obvious from early May to mid-June, corresponding with upper soil layer temperatures reaching 18°C. Female midges lay eggs along the veins on upper leaf surfaces, often in clusters.  After hatching, larvae move down within the leaf sheaths and puncture a stem node. This causes characteristic transverse swellings. Once larvae reach approximately 5.0 mm in length, normally 6-8 days, they fall to the ground and can burrow to a depth of 10 cm, before entering diapause. They can survive in the soil for more than one year and it is known that couch grass and ryegrass are suitable alternative hosts.

In an effort to better understand this pest, Dow AgroSciences are working closely with agronomists and growers who have previously experienced losses caused by this pest. We hope to learn more of the best timing for control and, based on our extensive knowledge of controlling Orange Wheat Blossom Midge, the effects of Dursban* WG.

Broadway* Star offers excellent control of wild oats including ‘fop/dim/den’ graminicide resistant populations.

The additional control of a range of broadleaved weeds offers farmers excellent value for money and will negate the need for more complicated tank mixes with wild oat specific products and those for broadleaved weed control. It will also help avoid the need for minimum sequencing intervals between certain wild oat and broadleaved weed herbicides - taking away another headache.

When applied for wild oat control Broadway Star will control all the following broadleaved weeds:

etl=established true leaves   

Optimising the Wild Oat control with Broadway Star

• Use on all varieties of winter wheat, winter rye and triticale
• Apply at 265g/ha in 130-150 litres of water
• Needs to be applied with an adjuvant – range supported
• FINE – MEDIUM spray quality
• Supported through a range of nozzles including Flat Fan Nozzles, Billericay Bubble Jets, Hawk Nozzles, VP Jets and Airtec Nozzles
• Need active growth of the target weed – soil temp of 8˚C and rising
• Rainfast 1 hour
• Crop at GS 11-32 inclusive
• Weeds within correct growth stage
  • Wild Oats    GS 12-30

Tank Mixes on Winter Wheat

• Can be tank mixed with a wide range of fungicides including chlorothalonil
• Can be tank mixed with pyrethroids, herbicides and trace elements
  • Tank-mixing Broadway Star 265 g/ha + 0.5 lt/ha Spitfire* offers a clean-sweep of many broadleaved weeds-many at larger sizes and an even wider spectrum of broadleaved weeds including Black Nightshade, Docks (from seed), Fumitory and Parsley-piert
• Tank mixes with growth regulators:
  • Do not tank mix with any growth regulator other than a ½ dose of straight Chlormequat
  • Any other growth regulators allow a 7 day interval
• Allow a 14 day interval between an OP insecticide  and Broadway Star
• In spring allow a 4 week interval between Broadway Star and PDM
• In spring allow a minimum 4 week, ideally 6 week interval between CTU and Broadway Star
• Wide range of permitted ALS joint applications.  Includes branded combinations of florasulam, metsulfuron-methyl, thifensulfuron-methyl and tribenuron-methyl

Learn more about Broadway Star 

As the warm weather through April is coupled with the recent rains, it will result in rapid softer growth of weeds, and will encourage broadleaved weed germination. Under these conditions Boxer* is not the ideal product of choice as it is most efficacious in cold, slow growing conditions.

Spitfire*, the new broadleaved weed herbicide from Dow AgroSciences has a very broad-spectrum which should prove useful as this spring flush emerges. Typically during April we experience fluctuating diurnal temperatures making Spitfire an ideal choice for broadleaved weeds including cleavers.

Key label and "non-label" weeds controlled include:

*Requires addition of MSO adjuvant
etl=established true leaves    MS = moderately susceptible at 2-4 etl    - = no information

Actions

• Where susceptible broadleaved weeds have emerged use Spitfire now
• Recommendations currently on farm for Boxer can remain provided the farmer is going to spray them while their growth is slow.
• Recommendations currently on farm for Boxer which the farmer will not have time to spray while growth is slow will need changing into Spitfire.

Benefits of Spitfire

• Use on all winter and spring cereal crops (except durum wheat)
• Can be applied up to GS 45 in winter wheat and winter barley
• Controls wide range of damaging broadleaved weeds
• Gives robust control from early autumn to late spring
• Tremendous tank mix flexibility
• No cultivation requirement for following crops
• Spitfire takes the guesswork out of broadleaved weed control

Learn more about Spitfire

To maximise yield from cutting and grazing swards, it is important to consider weed control while the weather favours plant growth. When targeting nuisance perennial weeds such as docks, nettles and thistles it is important to apply herbicides when the plants are actively growing.

Most herbicide applications to silage ground occur prior to or just after first cut. Depending on cutting date, the quality and quantity of silage taken will vary, placing great importance on achieving the best first cut possible.

Perennial weeds such as docks can significantly affect both the quantity and quality of grass harvested in silage fields. It is therefore very important to control these weeds, where possible, before the first cut of silage is taken. For optimal control, Doxstar* should be applied at 3.0 l/ha to docks when they are actively growing, at the rosette stage and not under stress. Translocation of herbicide to the root will be maximised where cutting is delayed for 3-4 weeks after application.

Good levels of weed control can also be achieved in grazing leys at this time of year.
Where mixed weed populations are present, including docks, nettles and thistles,  Pastor* is the most appropriate product to use. Where the weed spectrum is more specific, consider Doxstar for docks and Thistlex* for thistles.

Treat weeds at the rosette stage, when they are actively growing. If stem extension is already occurring, use a mechanical topper first, and then treat regrowth when it reaches the correct stage.

Summary

• Assess weed populations before first cut silage is taken
• Assess weed populations, and plant size, in grazing leys
• Where treatment is necessary, make applications at the rosette stage of growth
• Weeds must be actively growing to achieve best results
• Use Pastor for mixed weed populations
• Use Doxstar for docks
• Use Thistlex for thistles
• Maintain recommended water volumes for best results
• 7 day stock exclusion period
• 28 day cutting interval
• Excellent grass safety from all products

Keep weeds out of grassland with Dow AgroSciences’ excellent range of herbicides.

Review Critical Success Factors for further information and guidance.

Learn more about docks 

Learn more about nettles 

Learn more about thistles 

Learn more about Doxstar

Learn more about Pastor 

Learn more about Thistlex

Are Florasulam and Pyroxsulam SUs?

No, they are Triazolepyrimidines which give agronomists and farmers a number of key advantages over SUs.

Both Triazolepyrimidines and SUs mode of action is inhibition of ALS (branched chain amino acid synthesis).However there are key differences and benefits of Triazolepyrimidines like Florasulam and Pyroxsulam over SUs including:

• Inherently short soil half life – the benefit of which is markedly lower risk to following crops. Hence why with both florasulam and pyroxsulam there is no need to undertake any cultivations prior to sowing any following crop even autocast winter OSR.
• With broadleaved weeds there is no total cross resistance from sulfonylurea’s to triazolpyrimidines – the benefit of which is, to date florasulam still controls SU resistant broadleaved weed species with proven PRO197 resistance e.g. chickweed.

What does frost damage in WOSR look like?

We have received reports of frost damage in rape.  ADAS are also reporting damage.

Typically the pith is brown and hollowed within the stem and root.

Mildew is around. How do I use Fortress to control it?

Mildew is infecting crops particularly in the south west. An application of Fortress* will complement any fungicide programme and ensure mildew is not a problem for at least 4 weeks, and in many cases for up to 8 weeks. In barley 0.1lt/ha at T1 will give about 4 weeks protection of new growth, in wheat apply at 0.15lt/ha at T1.

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/16442/1011/G" on your training record. These details apply until 31st May 2011.

Use plant protection products safely.  Always read the label and product information before use.

*Boxer, Broadway, Doxstar, Dursban, Fortress, Pastor, Spitfire and Thistlex are trademarks of Dow AgroSciences LLC.

All other brand names are trademarks of other manufacturers for which proprietary rights may exist.

Boxer contains florasulam
Broadway Star contains pyroxsulam and florasulam
Doxstar contains triclopyr and fluroxypyr
Dursban WG contains chlorpyrifos
Fortress contains quinoxyfen
Pastor contains clopyralid, fluroxypyr and triclopyr
Spitfire contains fluroxypyr and florasulam
Thistlex contains clopyralid and triclopyr
 

More info at www.dowagro.com/uk