New herbicide for OSR this autumn

Syngenta has announced the UK approval of residual herbicide Teridox for use in oilseed rape crops this autumn.

Containing the active ingredient dimethachlor, it is seen as a product that can complement or replace metazachlor and provides activity on a range of grass and broad-leaved weeds.

“The highly competitive chickweed, red dead-nettle, mayweeds and groundsel, for example, are extremely well controlled,” said Chris Charnock, oilseed rape technical manager at Syngenta.

Novall – metazachlor + quinmerac
Springbok – dimethenamid + metazachlor
Teridox – dimethachlor

Used widely across continental Europe in pre-formulated mixtures, the availability of the active as a straight will give UK growers and agronomist’s flexibility to use Teridox in tank mixes tailored to individual situations, Mr Charnock explained.

“Stacking these herbicide actives is also a useful technique to aide in grassweed control.”

Currently approved as a pre-emergence herbicide only, the popularity of the product will be dependent on how the cost stacks up when compared with other pre-emergence options, said Jim Orson, crops and agronomy adviser at NIAB TAG.

“Will it offer better value than the formulated products such as Novall and Springbok? We will have to wait and see, as no one has much experience with the product.”

The other key issue is whether it will stand up as a straight substitute for metazachlor, continued Mr Orson. “In a tight oilseed rape rotation that would be particularly useful, with the restrictions now placed on metazachlor use,” he said.

This is a view shared by Mark Hemmant, technical manager at Agrovista, one of two distributors that will market the product this season, along with Hutchinsons.

“Where growers are unable to use metazachlor because they have exceeded the 1,000g/ha limit over three years, it should provide a useful alternative with a similar weed control spectrum,” said Mr Hemmant.

“That can be bolstered by adding clomazone and/or napropomide where necessary. It is also thought to be stronger in drier or trashy seed-bed conditions due to its higher solubility,” he added.

“It’s a welcome addition to the oilseed rape herbicide armoury, but only available in small quantities this year so it’s a bit of a look and see.”

Adam Clarke on G+

More on this topic

Read more on autumn herbicides