19 April 2002

Two-spray option is on…

By Andrew Blake

WHEAT growers already economising on fungicides following cool dry weather and lower product prices could now benefit from a move to a two-spray fungicides programme, weather permitting.

Earlier fears that the warm March spell might require many crops, especially those drilled early, to be treated sooner than usual, so stretching the T1-T2 spraying gap, have largely been dispelled.

Many growers may now be considering two instead of three-spray programmes, especially given the flexibility of newer products like Opera (pyraclostrobin + epoxiconazole), says Dick Neale of Cambs-based distributor Hutchinson.

After a cold dry three weeks most T1s are only being applied this week, notes Masstocks technical manager Clare Bend. That means the gap to flag leaf emergence, usually May 15-20, is back to a more normal four to five weeks. "Most chemicals give you the sort of persistency needed to get there."

Where T1 sprays have gone on at reasonable rates the greater flexibility of new strobilurin chemistry could now be exploited at the next spray timing to avoid the need for a third spray, suggests Mr Neale.

The new products, Opera and Acanto (picoxystrobin) offer greater kick-back curative activity, allowing flag leaves to be kept clean with a later T2 timing, plus enhanced persistence to keep the crop protected later into the season.

"Twists protectant activity, used with a triazole partner for curative activity as required, is an option at an earlier T2 timing because of its longer-lasting protection. Amistar would be an alternative where brown rust is a concern."

Post-T1 costs will depend very much on disease pressure, he notes. "So its too early to say what you might have to spend. There is no right tool for the job. If you are looking at Opera you are into £28+/ha"

For about £5/ha more than 0.5litres/ha of Landmark (kresoxim-methyl + epoxiconazole), Opera at 0.6litres/ha offers better kick-back curative activity and greater persistency, adds Northants AICC agronomist Justin Blackwood.

But Opponent, available from Agrovista and Cropwise at much the same price and including kresoxim-methyl (as in Landmark), is probably an even better buy for the T2 slot, he believes.

The main opportunities for economising lie with resistant varieties, notes Mrs Bend, particularly where straight pyraclostrobin (as in Tucana from Masstock, Comet from UAP and Vivid from ProCam) can be used with a triazole rate tailored to variety and disease pressure at the time.

But resist the temptation to cut fungicide doses too far, she advises. "Rock bottom grain prices are far more likely to be achieved when you cut back on fungicides and forget about protecting bushel weight."

Senior ADAS consultant David Parish agrees. There is a real danger that growers could cut doses too hard, either for outstanding T1s or at the key T2 flag leaf timing, either in reaction to apparently low disease levels or rock-bottom grain prices — or both, he warns. &#42

&#8226 See p66 for barometer farmer T1 tactics.

@NH24:Value fungicides

@BT:Triazole fungicide prices have fallen 30% in the past three years and older strobilurins are about 50p-£1/ha cheaper than last season. The new p-strobs, based on picoxystrobin (as in Acanto) and pyraclostrobin (as in Opera and others) typically cost 10-15% more than older strob products. But quotes for the latter recently ranged from £153-£175 for five litres, highlighting the scope for bargains.

@KB:Towards T2

Most T1 sprays only just completed.

T1-T2 gap back to normal.

New strobs offer more flexibility at T2.

Two-spray programme an option.

Strong competition between suppliers.

Value fungicides

Triazole fungicide prices have fallen 30% in the past three years and older strobilurins are about 50p-£1/ha cheaper than last season. The new p-strobs, based on picoxystrobin (as in Acanto) and pyraclostrobin (as in Opera and others) typically cost 10-15% more than older strob products. But quotes for the latter recently ranged from £153-£175 for five litres, highlighting the scope for bargains.

TOWARDST2

&#8226 Most T1 sprays only just completed.

&#8226 T1-T2 gap back to normal.

&#8226 New strobs offer more flexibility at T2.

&#8226 Two-spray programme an option.

&#8226 Strong competition between suppliers.