24 July 2002

BYDVsignals need for seed treatment

By Andrew Blake

WINTER cereal crops are facing potentially severe BYDVlosses this year. But growers who chose the right seed treatment last autumn have a brighter outlook, according to Exeter-based crop specialists Matford Arable Systems.

Last autumns fine weather encouraged many to plant early. But against a backdrop of low grain price futures, some decided to gamble with their seed treatment.

Barley Yellow Dwarf Virus (BYDV) is now showing in many of the early-drilled crops and especially those that were not protected with Secur (imidacloprid) seed treatment, either by itself or in a programme with pyrethroid sprays, necessary on the most vulnerable crops drilled before the end of September, it says.

Last autumn was particularly bad, the suspicion being that the fly-in of aphids continued into December, with more flying in and infesting the crops during April, says Stuart Wilson of Bayer. "The problem was particularly prevalent in the coastal regions of the south-west."

Technical director for Matford Arable Systems, Neil Potts, believes this year could be one of the worst for widespread BYDV pressure.

"We have seen worse years in the past in terms of severity, where whole crops have been wiped out, but this year, with early drilling, late aphid fly-in, poorly timed spraying or non-Secur-treated crops, the problem is certainly very widespread," he says.

Some affected barley in the west could see yields down by 30-35% and wheats reduced by 10-15% this season from BYDV or take-all, Mr Potts suggests. "To contemplate drilling early wheat without Secur seed treatment is virtually suicidal," he adds.

Managing director of Matford Arable Systems, Peter Ash, drilled a field-scale comparison at his own farm, Matford Barton, near Exeter. The 16ha (40 acre) comparison is between a standard seed treatment and Baytan Secur.

On this light and drought-prone land, the plant growth regulatory effects of Baytan have helped promote better and deeper root development while the Secur element has added protection against early BYDV infection.

The experience gained at Matford Barton helps Mr Ashs team of agronomists give advice to fellow West Country grain producers. This year the team has seen dramatic difference between crops treated with Secur and those not.

"Good establishment is vital, get that wrong and youre on the back foot from the start," says Mr Ash. "In my comparison the Secur part of the seed treatment has undoubtedly had a big effect for little extra cost, and in the future I wont be planting anything here unless it has been treated with Secur," he explains.

Secur is an imidacloprid-based product that gives early protection against the aphid-borne virus BYDV. It also gives useful control of slugs, wireworm and a range of other pests. When combined with Baytan it becomes a powerful management tool in the production of quality cereals. &#42

BYDV PRESSURE

High pressure last autumn.

Widespread symptoms now.

Consider Secur with or without pyrethroid spray for pre-October crops.

BYDVis showing in far too many crops, says Peter Ash of Matford Arable Systems. Extra care will be needed this autumn to avoid a repeat.

&#8226 High pressure last autumn.

&#8226 Widespread symptoms now.

&#8226 Consider Secur with or without pyrethroid spray for pre-October crops.