Emerging grassweeds need treating now, says Dow AgroSciences

UK - November 08, 2012

The time for post-emergence grassweed treatment is rapidly approaching, according to the latest Dow AgroSciences’ Grassweed Emergence Monitor.

GEM monitors drilled fields at sites in Cambridgeshire, Oxfordshire, Herefordshire, Wiltshire and North Yorkshire.

Blackgrass emergence remains slow in Oxfordshire (GS7-9), Herefordshire (GS9-10), and North Yorkshire (GS5-11) with steady emergence in Wiltshire (up to GS12).

New product UNITE (pyroxsulam and flupyrsulfuron-methyl) is best used where blackgrass is the driver weed and at the one to three leaf stage (GS11-13).
In Oxfordshire sterile brome and Italian ryegrass have reached GS7-9 and are growing rapidly. Growth in Wiltshire has been slower but these weeds are now up to GS12. Emergence is now beginning in North Yorkshire and they are up to GS11. In Herefordshire there has been little further emergence. Italian ryegrass is up to one leaf and sterile brome up to three leaves.

Dow AgroSciences’ product Broadway Star (pyroxsulam and florasulam) should be applied now on winter wheat where ryegrass, wild oats and bromes are the driver weeds. 

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

Optimal timing for pyroxsulam-based products is when the weeds have germinated but before they get too large, which can be achieved this autumn.

Stuart Jackson, cereals specialist at Dow AgroSciences, says: “Even though this has been an incredibly challenging autumn at the moment the conditions are conducive for using ALS chemistry. Unlike last year blackgrass emergence is slow and plants are small. The soil temperatures are looking good and once a window of opportunity comes, post-emergence treatments will be vital to maximise yield potential and financial returns from late drilled, backward crops.

“GEM together with weather data helps agronomists and growers to work out when the flush of grassweeds is through and pinpoint the best spray timing.”