10 August 2001
New cleaver killer in pipeline

By Andrew Blake

TWO new developments, if they succeed, could make cleaver control easier, according Dow Agrosciences Lincolnchire-based agronomist Stuart Jackson.

Coded herbicides GF184 and GF185 combine fluroxypyr, as in Starane 2, with florasulam, the active ingredient in Boxer launched in spring 2000.

The firm hopes the products may be available in early 2002.

As well as offering wider cleavers treatment windows, they control a broader range of weeds than either Boxer of Starane 2 alone, says Mr Jackson.

Although there has been no tank-mix recommendation for Boxer with Starane 2, there has been nothing to stop growers mixing them.

“But a single product will give farmers more flexibility and insurance,” says Mr Mr Jackson.

“For example they need not worry if they bought in February but cant spray until May.”

Applied at around 1.8l/ha, Both products contain 100g/l of fluroxypyr, with GF184 having 2.5g/l and GF185 only 1g/l of florasulam.

Cleavers do not generally compete before crops reach second node (GS32), notes Mr Jackson. “But the longer they are left after that, the greater the potential for yield loss.”

Currently, growers have to choose between spraying against the weed relatively early with one material or striking later with an alternative.

“Typically you would think about changing from Boxer or Starane 2 about mid-April.”

In GF184, growers should have a more “robust season-long” product that can be used anytime between Feb 1 and GS39 (flag leaf emergence), he says.

GF185 is seen as a “mid-late” season alternative to straight Starane 2 offering a wider weed control spectrum.

In particular the florasulam adds control of mayweeds and brassicas, he notes. The only slight drawback is that the latest application stage will be GS39, rather than Starane 2s GS45.

As a triazolopyrimidine, florasulams ALS-inhibitor mode of action is similar to that of sulfonylureas.

“With the new products there may be certain restrictions associated with following crops, tank-mixing or sequencing,” advises Mr Jackson.

“They should be OK to use after Lexus and Lexus DF, based on the current Boxer registration, but not after Lexus Millennium nor for the moment Monitor.”

Approval for use on all winter and spring varieties of wheat, barley, oats, rye and triticale is being sought for both newcomers.