PODCAST: Focus should be on topping up disease control at ear spray timing in wheat

Agronomists and pesticide manufacturers are predicting widespread use of T3 ear sprays in wheat this year, but the focus will be on topping up foliar disease control rather than mycotoxin suppression.

JSR Farms would be applying an ear spray to all 1500ha wheat, regardless of whether it was for feed or seed, farms director Philip Huxtable said at a BASF-organised round table discussion.

“Five or six years ago we didn’t bother with a T3,” he said. “Now they’re done as a matter of course. We’re after yield, so it doesn’t make sense to fall at the last hurdle.”

He was clear about the role of the ear spray. “We use it to extend foliar disease control and keep the leaves green. Fusarium isn’t an issue for us here in east Yorkshire and the topic of mycotoxins has never even been mentioned by our buyer.”

The farm was in a low-risk area for fusarium, he admitted. “We also don’t have any maize in the rotation and we plough. So we’re not at all likely to have a problem.”

The location of the farm, near Driffield, meant it benefited from a long, cool grain-filling period. “So the T3 spray is always going to be aimed at the disease which affects yield – usually septoria.”

Ear sprays

Ear sprays are likely on most farms this spring

AICC member Steve Cook of Hampshire Arable Systems, who advises growers in Hampshire and Berkshire, had more milling wheats in his area, as well as much more maize in the rotation.

“It’s a high-risk area for fusarium,” he noted. “But it’s still foliar disease top-up we’re looking for from a T3. If we get fusarium control as well – that’s a bonus.”

Fusarium control was only achieved by pinpoint accuracy with spray timing, he pointed out. “It’s a very tight window. Not many growers can get round all of their wheat in the one week it is flowering.”

Good fusarium control called for higher fungicide rates, he added. “You need to go up to three-quarters rate and that makes it expensive. So we have to be realistic when advising farmers, as so much depends on the season.”

For Graham Brooks of Prime Agriculture in Essex, where milling and biscuit wheats were being grown, the T3 spray was always planned.

“It covers all eventualities,” he stressed. “When we design a disease control programme at the start of the season, we don’t know what the weather will bring. We may not always need to use a T3, but there’s enough evidence to show it brings an average 0.4t/ha benefit.”

He didn’t pitch the ear spray at fusarium control either. “There’s a cost issue. By the time we get to T3, many growers believe they’ve spent enough. So we’re not looking to spend more than £12/ha.”

Fungicide choice at T3 depended on the end market, each agreed. Mr Huxtable was taking the ‘cheap and cheerful’ tebuconazole route with his feed wheats. On the higher value seed crops, he was opting for Swing Gold.

Tebuconazole’s loss of efficacy against septoria didn’t worry him. “We’re going into clean crops anyway. Most of the job has been done by the T1 and T2 sprays, so we don’t need to spend more than £7/ha.”

But Mr Cook had replaced tebuconazole with metconazole on feed wheats, because of performance concerns. Milling wheats would be getting a mix of prothioconazole with a strobilurin. “That will most likely be Firefly, as it’s the cheapest way to buy the prothioconazole we need.”

Firefly would cost £15-20/ha, he calculated. “We’re using a strobilurin to help protect the ear and give any rust control we need.”

Mr Brooks was also advising a triazole/strobilurin mix at T3. “We’re going for prothioconazole plus Comet. The idea is to combine the rust activity from the strobilurin together with foliar disease control plus any mycotoxin suppression from the triazole.”

See: Ear sprays pay three years out of four, according to TAG

Active ingredients

  • Cometpyraclostrobin
  • Fireflyprothioconazole + fluoxastrobin
  • Amistar Optiazoxystrobin + chlorothalonil
  • Amistarazoxystrobin
  • Swing Goldpyraclostrobin + epoxiconazole

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