Maker blows cool on debutant strobs stretch potential
Maker blows cool on debutant strobs stretch potential
By Andrew Swallow
DESPITE repeat results demonstrating the opportunity to stretch spray intervals with next generation strobilurin F500 (pyraclostrobin), manufacturer BASF is advising against a two-treatment regime in wheat next year.
Unparalleled curative activity from the strobilurin, which BASF says exceeds even triazole standard epoxiconazole, suggests T1 to T2 spray intervals can be increased without loss of yield.
Indeed, harvest 2001 results from Morley Research Centre show yield was not significantly reduced by cutting back from a three-spray programme to a stretched GS31-GS55 two-spray programme.
Yield in 2000 was even increased significantly by the reduced pass programme with F500 + epoxiconazole.
However, technical business manager Steve Waterhouse is adamant two sprays is too risky. "If you decide to delay to GS55 then it rains and you cant get on you are in real trouble. We have asked the same question with stretched Landmark programmes and proved quite clearly that it can be broken in difficult years.
"It would be irresponsible of us to encourage dramatic changes to spray programmes."
Yet he admits F500 is a different animal to Landmark and other current strobilurins.
"It is another revolution in disease control – equivalent to the jump from triazoles to strobilurins. No longer does strobilurin stand for protectant."
Despite its curative capabilities, BASF will not recommend pyraclostrobin use alone. "It is essential to include epoxiconazole for consistency of yield, to maximise cost effectiveness and as an anti-resistance strategy," he stresses.
So far, only the active ingredient has received provisional approval from the Advisory Committee on Pesticides. The company is awaiting clearance for marketing a raft of formulations so cannot say whether a straight formulation will be available, says fungicide product manager Tony Grayburn.
"What I can say is that even if we were to market it as a straight formulation, it would only be in a combination with epoxiconazole."
BASF believes F500s broad-spectrum foliar disease control (Arable, Jun 1) will be of most benefit on the flagleaf. But like Landmark an F500 + epoxiconazole formulation does give a moderate level of eyespot control, so could equally be used at T1.
"It has at least the level of eyespot activity that Landmark does. Its a benefit for no extra expense," notes Mr Waterhouse.
However, what that expense will be and where it leaves Landmark in the fungicide market are unclear.
"The plant for F500 is built and running, but the price decision has not been taken yet," says Mr Grayburn. *
PYRACLOSTROBINREVOLUTION
• Step up on current strob standards.
• More curative than best triazole.
• Mixing still essential.
• Eyespot angle at T1.
New strobilurin fungicide pyraclo- strobin is more curative than epoxi- conazole, but resistance risks and yield response still make mixes essential, says BASFs Steve Waterhouse.