STROBILURINS STILL offer worthwhile yield benefits, despite high levels of resistance, latest trial results have shown.

The independent and Syngenta-funded trials found that despite UK Septoria tritici resistance levels averaging 95% by the end of the 2004 season, strobilurins could still provide a yield benefit of up to 0.4t/ha.

“To get the best returns from strobilurins, it‘s vital farmers now choose them principally to protect against other diseases – such as take-all, rusts and ear diseases,” said the firm‘s Matt Pickard.

In the trials, the best wheat yields were achieved when strobilurins were applied at flag leaf and ear emergence (T2 & T3), he said.

“Use at these timings not only allows strobilurins to be targeted against a wider range of diseases, but also allows advantage to be taken of their crop greening effects closer to grain-filling.”

But where take-all or early season yellow rust are the main problems, earlier use (T1 & T2) of a strob with specific label approval against both diseases is likely to be more effective, he said.

Mixing strobilurins with other fungicides can help protect against resistance development, as well as providing effective disease control, added the firm‘s Dietrich Hermann.

“For robust disease control, strobilurins have to be mixed with other fungicides,” he said.