A new higher dose has been approved for cereal fungicide Cherokee (propiconazole + cyproconazole + chlorothalonil), its maker’s Syngenta have announced.

The new approval will allow a maximum individual dose of 2.0 litres/ha rather than the previous maximum of 1.5 litres/ha. A new maximum total dose of 4.0 litres/ha per crop has also been approved.

It effectively meant growers could increase the robustness of their disease control according to disease risks, Matt Pickard, the firm’s cereal disease specialist said. “With the higher rate growers will have more flexibility to adjust its use according to disease pressure or to the level of curative activity needed against existing infection.”

As examples, where growers had considered either 0.5 litres/ha of prothioconazole or 0.6 litres/ha of epoxiconazole mixed with Bravo (chlorothalonil), Mr Pickard suggested they could now consider Cherokee at up to 1.75 litres/ha.

Alternatively where higher doses of 0.6 litres/ha of prothioconazole or 0.75 litres/ha of epoxiconazole had been mixed with 1.0 litres/ha of Bravo, he pointed to Cherokee at 2.0 litres/ha.

“Cherokee provided growers with a high concentration of two different triazole fungicides, plus the anti-resistance component of Bravo, rather than targeting disease with a single triazole. In trials it has give comparable yields to mixtures of alternative triazoles with Bravo, but at a lower cost per hectare.”

In addition, trial plots last year showed using Cherokee in early season spray programmes had a straw shortening effect in wheat, he said. “With high lodging pressure being forecast as well as high disease pressure, this could be a useful spin-off from including Cherokee.”

The product would be available in a new formulation this year which didn’t require a separate compatibility agent, he added.