17 August 2001

Cleavers killer in product pipeline shows promise

By Andrew Blake

CONTROLLING cleavers in cereals could become easier if Dow Agrosciences succeeds in developing two new products, according to the firms Lincs-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. For example they need not worry if they bought in February but cant spray until May."

Both products contain 100g/litre of fluroxypyr, with GF184 having 2.5g/litre and GF185 only 1g/litre.

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. "With Starane 2 you can go right up to GS45 of the crop."

As a triazolopyrimidine, florasulams ALS-inhibitor mode of action is similar to that of sulfonylureas. "So with the new products there may be certain restrictions associated with following crops, tank-mixing or sequencing.

"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, which is something we need to address as soon as possible."

Approval for use on all winter and spring varieties of wheat, barley, oats, rye and triticale is being sought for both newcomers. &#42

CLEAVER COMBINATIONS

&#8226 Two development products.

&#8226 Mixtures of current actives.

&#8226 More flexible and wider weed control.

&#8226 Hopes for early 2002 launch.