23 June 1995

Ear sprays are essential – but which disease is main threat?

EAR sprays are a must for wheat growers across the country this season, according to experts. But which disease poses the biggest threat is open to debate.

Norfolk-based Simon Draper, chairman of the Association of Independent Agronomists, reckons fusarium is the main worry. "It has been wet and cold in the east for three weeks; ideal for the disease."

Other areas could need spraying, too. Flag-leaf sprays leave ears largely unprotected, says colleague Alan Bide.

Both recommend half-rate Silvacur (tebuconazole + triadimenol) in 100 litres/ha (9gal/acre) of water at the end of flowering if dull weather persists.

"No chemical is particularly active on the disease, so timing is more critical," says Mr Draper. At £15/ha (£6/acre) it is good insurance and boosts protection against leaf disease, he adds.

There is little to choose between varietal resistance, says Mr Bide. National Institute of Agricultural Botanys Richard Fenwick largely agrees but picks out Spark as good and Rialto as one to watch.

"Most varieties are rated 5 or 6 for fusarium. In practice they would get fusarium in a bad year. But Spark has a 7 – in the wet it is a clean-ripening variety. Rialto, on limited data, is rated at 4, so could be worth spraying."

ADAS disagrees

Bill Clark, ADASs national cereal pathologist, disagrees. "Most wheats will need an ear spray but not for fusarium. It is too late for most crops – they need spraying at the start of flowering as soon as pollen is about. Nationally, the disease is not a serious problem."

He is more concerned with leaf disease. Flag-leaves emerged early, so protection will be running out in crops sprayed then.

"A half-rate triazole applied now will help protect the ear from septoria and mildew. But it is more important in terms of topping up the flag leaf spray. There is a lot of disease about and crops have a long way to go before they are ripe."