Field comparisons highlight strobilurins early strengths

12 April 2002

Field comparisons highlight strobilurins early strengths

STROBILURINS – are they best deployed on the flag leaf and ear or will an early spray pay more?

That is the question many growers have been grappling with, including Peter Meikle, farm foreman of Hardingham Farms, Wymondham, Norfolk.

Historically he used strobilurin fungicide on the 284ha of winter wheat at flag leaf and on the ear. But two years of farm trials on the sandy clay loam have prompted a change this spring.

"I am still cautious, but the largest part of our programme will be at T1 and T2 this year, rather than the traditional T2 and T3 approach used around here."

Last year the early strobilurin programme proposed and part-funded by Syngenta (see table) outstripped his own fungicide programme by 0.75t/ha (0.3t/ha) on Claire. The previous year, using Twist (trifloxystrobin) in place of Amistar (azoxystrobin) produced very similar results with Consort.

Based on a grain price of £70/t, even allowing for the extra cost of the higher rates used in the trial field, that equates to £29.40/ha (£11.90/acre) extra margin. "That would add up to a few thousand pounds across the farm," he says.

This year all first wheat, except late-drilled crops after sugar beet, will receive a strobilurin at T1. On Claire that will be Acanto (pyraclostrobin) followed by Acanto or Amistar (azoxystrobin) at flag leaf, while on Napier a Twist (trifloxystrobin) flag leaf spray will follow Acanto at T1.

While rates have yet to be decided a lesson from the farm work is that a reasonable amount of product is needed to maximise margin. "We have all become a little too cost conscious I think. What really matters is margin over input cost."

However, Mr Meikle does not believe the early strob will pay on second wheat or late-drilled first wheat after sugar beet.

Syngentas area sales manager Simon Laidler acknowledges such instances are more marginal.

"But a responsive variety can still benefit. The aim is to keep the disease level low to provide the best foundation for the flag leaf spray. That will be particularly important this year with so many well-tillered, forward crops.

"As a rule we recommend strobilurins at T1 and T2 for maximum yield in feed wheat crops and T2 and T3 for quality in milling wheat." &#42

In the armoury, but when to deploy the weapons? Farm trial work has convinced Peter Meikle that strobilurins are worthwhile at T1.

Farm trial approach

Syngentas aim with its direct sponsorship of farm trial work is to expose its products to a wider audience and raise growers awareness of how to get the most out of them, says Mr Laidler. "We are trying to get growers to use our products in a situation where they have not tried them before. In return we rebate them part of the cost for the trial area." Several dozen farms are conducting such work across the country. "Generally we are only talking to farms who are not tied into a distributor agronomy package."

Timing Farm standard Sponsored trial

T0 0.1 Fortress 0.2 Fortress

T1 0.4 Unix 0.5 Unix + 0.4 Amistar

T2 0.5 Amistar + 0.4 Opus 0.7 Amistar + 0.4 Opus

T3 0.35 Amistar + 0.35 Folicur 0.5 Folicur

Cost* £57.55 £80.65

Yield 9.65t/ha 10.4t/ha

Margin/ha £618 £647

*Costs include pgr programme.

NB: Wheat @ £70/t, all Claire first wheat after OSR.

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