Free information for farmers facing blackgrass

UK - February 02, 2012

Week by-week information on the emergence of blackgrass and other grassweeds is available for free to help growers and agronomists optimise spray timings, thanks to Dow AgroSciences.

Its Grassweed Emergence Monitor (GEM) includes five winter wheat sites in Cambridgeshire, Herefordshire, North Yorkshire, Oxfordshire and Wiltshire and three sown major grassweeds: blackgrass, sterile brome and Italian ryegrass, together with a ‘natural’ unsown blackgrass population.

Four sites have been drilled so far: Oxfordshire, Herefordshire, Wiltshire and North Yorkshire. Cambridgeshire’s site is due to be drilled this week.

According to the latest GEM report, all sites are wet with soil temperatures around 10-11°C.

In Wiltshire, Herefordshire and Oxfordshire sterile brome and Italian ryegrass have emerged with a small proportion of blackgrass. Sterile brome and Italian ryegrass remain at the one to two leaf stage with blackgrass at one leaf. In contrast, North Yorkshire is yet to see any grassweed emergence. This has been the wettest of all the sites.

Stuart Jackson, cereals specialist at Dow AgroSciences, says: “A crucial step to achieving successful control of headache grassweeds in winter wheat, like blackgrass, ryegrasses and sterile brome, is to monitor when grassweeds emerge.

“This means that post-emergence treatments can be applied as soon as possible when the weeds are small and are actively growing.”

To help growers and agronomists understand growth of these weeds, Dow AgroSciences is funding the monitoring scheme, based on data from ADAS, once again this season. GEM first began in the autumn of 2010 and is received by 850 agronomists and farmers.

Dow AgroSciences’ products for grass and broadleaved weed control in winter wheat, UNITE and Broadway Star, are both ALS contact herbicides and optimal timing is when the weeds have germinated but before they get too large – ideal for this season’s conditions.

Mr Jackson says: “To get the best from UNITE and Broadway Star, the grassweeds are ideally treated before they begin to produce tillers and when conditions are good for active growth. GEM helps agronomists and growers to work out when the flush of grassweeds is through. Using this together with weather data you can help pinpoint the best spray timing. UNITE is best used where blackgrass is the driver weed and Broadway Star where ryegrass, wild oats and bromes are the driver weeds.  Add a residual as appropriate.
“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,” says Mr Jackson.

To receive GEM updates send an e-mail to DowAgroSciencesuk@dow.com, with the title Subscribe to GEM Updates and include your name, email address and company details.