Stretched fungicide timings risky

1 June 2001



Stretched fungicide timings ‘risky’

By Andrew Swallow

A LEADING agronomist is questioning the wisdom of stretching traditional fungicide timings, even with the prospect of a new more curative strobilurin.

This would be unwise, even when BASFs strobilurin pyraclostrobin, becomes available next year, says ADAS national cereal pathologist Bill Clark.

“In practice that is a dangerous route to go down,” warned Mr Clark. “It is better to get the timing right and adjust the dose rate, rather than stretch the gap.”

However, he believes that F500 is a cut above the strobilurins currently available.

BASF data shows that in a triazole mix it typically gives 0.5t/ha more yield than existing strobilurin-based fungicides.

“When we first saw it in action we couldnt believe it was a strobilurin,” said Mr Clark. “We didnt think we would ever have a strob with such eradicant action.”

Both BASF and Mr Clark stress the new strobilurin should not be used as a stand-alone product, despite its curative ability.

Adding a triazole reduces resistance risks, adds systemic action, and improves reliability of control, they say.

In any case, BASF has yet to decide whether it will be available as a straight.

Different combination have been trialled, but the only mix BASF can confirm will be marketed, subject to approvals, is an F500/epoxiconazole mix.

UAP technical director Chris Bean believes F500s main strength is its breadth of disease control.

However, he is unconvinced that it will represent the revolution in fungicides that manufacturers claim.

Agrovistas Colin Myram reckons F500 shows an edge on current standards for rhynchosporium control in trials this year.

BASF maintain its real strength in barley is on net blotch.

• New molecules, new standards, FWi, 16 December, 2000
• Strob cereal fungicides ready for battle, FWi, 17 November, 2000
  

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