Weather makes T3 spray a tough decision to call

Variable crop potential across the country is making ear wash decision-making tricky this season, according to agronomists. While the April drought had brought down yield potential in some crops, others looked promising, they suggested.

“It makes T3 an extremely difficult decision,” Brian Ross, a Bedfordshire-based agronomist for Frontier said on Tuesday (29 May). Good wheat prices favoured spending more at T3 to protect crops, particularly with heavy weekend rain likely to encourage septoria development, he explained.

But, with weather-delayed T2s going on relatively late and at robust doses, there was a case for “crossing fingers” and hoping crops had enough fungicide to see them through to harvest, he added.

Crop potential was very variable following the April drought. “Some earlier-drilled first wheats are looking good, particularly where nitrogen wasn’t delayed. Second wheats or wheat drilled after sugar beet are looking very thin. They didn’t put roots down and dropped tillers during the dry spell – the potential isn’t there.”

Steve Cook of Hampshire Arable Systems reckoned crops on less fertile soils had lost perhaps 1t/ha of potential yield during the drought. Thin crops wouldn’t intercept all the light available to them, he said. “With sunlight hitting the deck, light usage will be poor.”

TAG Consulting’s Peter Riley agreed yields had been hit. “Generally crops on the lighter soils in the Eastern counties suffered quite badly, and while later-sown wheats have recovered to a certain extent, yields could be down in those crops by 10-15% easily.”

Most of Mr Cook’s clients’ T2 sprays had ended up being applied as crops headed. “I’m holding back now for 10 days to see what the weather does.”

Feed wheats were unlikely to be sprayed again. “They got a three-quarter dose of Opus plus strobilurin plus morpholine in most cases, so it’s got to be exceptional weather to need to go back again.”

Milling wheat would probably be treated, but with a lower dose than if the flag leaf sprays had been applied before the ears were fully emerged. “It will probably be Proline or Folicur.”

Mr Riley suggested his T3s would need to be more robust than normal on some crops. “On the more backward wheats there has been a reduction in fungicides, but with the recent weather T2s have been more robust than planned on other crops, and ear sprays are likely to be as well.

“On septoria varieties I’m looking at maybe as much as a half rate Proline or Opus to top up control, and on rust varieties will also include a strobilurin as well.”

ProCam’s Nick Brown was also concerned by brown rust in his Buckinghamshire/Wiltshire patch.

“It’s beginning to frighten me. Good doses of fungicides have had little impact on rust on Alchemy. If it comes hot and dry it will have the chance to explode again.”

Septoria was less of an issue however, he said. “It’s been pretty well controlled and even though we’ve had rain splash it hasn’t got to the top of the plant.”

 




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