An alternative annual meadowgrass and broadleaved weed herbicide is being test-marketed this autumn by Bayer CropScience.

Othello (mesosulfuron-methyl + iodosulfuron-methyl-sodium + diflufenican) is being launched as an alternative to the traditional IPU / DFF mixes used to tackle annual meadowgrass and broadleaved weeds. The Pesticides Safety Directorate has announced IPU will be withdrawn from sale by June 2009.

Applied at 1 litre/ha with the adjuvant Biopower, it had both contact and residual activity, with a flexible application window up to GS32 (second node detectable), Tim Holt of Bayer said.

“However, the optimum timing for application is at the 2-3 leaf stage of annual and rough-stalked meadowgrass, when the majority of weeds have emerged.

The product is most effective when there is active weed growth, adequate soil moisture and the weeds are not under any stress. “It will work best going into a cold spell rather than following very cold conditions,” Mr Holt said.

Othello is the first ODesi (oil dispersion) weed killer to be launched by Bayer in the UK. A limited amount will be available this autumn, so growers can try the product before IPU is withdrawn. An official launch is planned for Cereals 2008.