Grassweed Emergence Monitoring (GEM)

What's GEM?

A crucial step to achieving successful control of headache grassweeds in winter wheat – blackgrass, ryegrasses and sterile brome, is to monitor when grassweeds emerge, so that post-emergence treatments can be applied as soon as possible when the weeds are small  and are actively growing. To help growers and advisers understand growth of these weeds, Dow AgroSciences is funding an ADAS monitoring scheme once again this season.

This year, GEM includes:

  • Five winter wheat sites: Cambridgeshire, Herefordshire, North Yorkshire, Oxfordshire and Wiltshire
  • Three sown major grassweeds: Blackgrass, sterile brome and Italian ryegrass (all sown 500 seeds/m2) and a 'natural' unsown blackgrass population
  • Two staggered drilling dates

It is important to remember that germination of grassweeds will also be subject to local factors and the information provided by GEM should supplement but not replace field monitoring.

Report 5 - 22nd November 2012

Up until yesterday we have had two weeks of fairly consistent weather with average maximum temperatures around 11-12°C and average minimum temperatures around 3-4°C. All sites experienced frost on 18th and 19th.  Soil temperatures (at 30cms) have risen slightly to just under 9°C.

A dry week in Cambridgeshire allowed more drilling to occur in the locality.  It is now much wetter once again!

In Herefordshire there has been no further emergence of any species. Sterile brome is at 3-5 leaves and Italian ryegrass and blackgrass up to 1 leaf.

In Wiltshire sterile brome and Italian ryegrass continues to emerge steadily but blackgrass emergence has tailed off.

In North Yorkshire all species are at 1 leaf with no further emergence.

In Oxfordshire blackgrass continues to emerge but there has been no further emergence of sterile brome and Italian ryegrass. All species are up to 1 leaf.
In Cambridgeshire there has been no emergence of any species as yet from a sowing date of 7th November.


 

 

All sown grassweeds are drilled at 500 seeds/m2

Please note all emergence is cumulative - early emergers will be getting bigger as grasweeds grow.

Current advice for grassweed control in winter wheat:

Grassweeds are growing. Optimal timing for pyroxsulam-based products is when the weeds have germinated but before they get too large. Some fields which were drilled in September and early October are ready for treatment but difficult travelling conditions are preventing application or recommendations need to be changed. Dow AgroSciences are aware planned programme applications have been missed and have issued advice for controlling blackgrass here and bromes, wild oats and ryegrass here in what is a challenging autumn. Whilst you are waiting for conditions to come right take a look here at our experiences last year.

If grassweeds and crops are now at the correct stage for post-emergence treatment and you can travel, apply UNITE or Broadway Star.

Use UNITE where blackgrass is the driver-weed.  For all grassweed situations, apply UNITE + adjuvant with a residual partner.

Use Broadway Star where ryegrass, wild oats and bromes are the driver-weeds.  Add a residual as appropriate.

Learn more about UNITE

Learn more about Broadway Star

 

If you would like to receive our GEM Updates by e-mail, please send an e-mail to DowAgroSciencesuk@dow.com, entitled Subscribe to GEM Updates.  Please include your Name, E-mail address and Company details and we will add you to our subscription list.