12 May 1995

Oilseeds under pressure

PARCHED topsoils and flea beetles have been putting spring oilseed sowings under severe pressure.

Scorching weather sucking moisture from the land left many crops, especially those later drilled, desperate for rain.

"Sixty per cent of the linseed and spring rape is coming through OK and overcoming any problems," says Nick Cooper of Guildford ADAS. But 40% is "struggling" to establish against flea beetles in dry soils.

Head start

Early signs are that Vitavax RS (carboxin + gamma-HCH + thiram) seed treatment is giving linseed a "head start" against the pests, says Dr Jenny Smith of ADAS Bridgets. Even so, treated crops have had to be sprayed twice to counter "significant damage". Winter linseed, which generally escapes the pests attentions, looks good at Bridgets and could prove a useful alternative in future, she says.

Most oilseed crops drilled into moisture in early April have established well, says Steve Cook of Hampshire Arable Systems. "But flea beetle is on everything. Hopefully with some moisture theyll grow away from it. But Ill be concerned if it stays cold all week."

"Crops really are starting to show the lack of rain," says Dr Mike Carver of Cirencester-based ARC. Yields dip fast as dry weather renders fields effectively late-sown, he points out. Flea beetle has been a "real problem".

United Oilseeds Sussex-based fieldsman Ian Pugh acknowledges the problems – one rape field drilled four weeks ago on Romney March has only 5% germinated, he reports. "But there is less spring rape about this year."

Concern is not confined to the south. Linseed at farmers weeklys Easton Lodge Farm, near Stamford, Lincs, was hit hard by flea beetle as soon as the weather warmed up, reports manager John Lambkin.

A single cypermethrin spray has "done the job". But more rain to complement residual reserves will be vital for a decent yield, he says.

Linseed growth is "spasmodic – all over the place", says AICC crop consultant Andy Morrison of Oakham, Leics. "It ranges from the cotyledon stage to pre-germination."

Spring rape is more even. In most fields, plants have cotyledons. "But crops definitely need some warm rain," he adds. Heavy dews helped relieve stress, but recent hot weather did "no favours at all".

Fortunately flea beetle damage has been less than anticipated, says Mr Morrison. One application of cypermethrin has kept it in check so far.

Andrew Fisher, of Yorkshire Arable Advice at Harrogate, says nothing is harming at the moment, but that could change without rain. "Spring rape and linseed are looking pretty moderate at the moment – they desperately need water."

Flea beetles have now appeared. "Its the first time we have seen them in this area."

Rain in Scotland over the weekend came just in time to offset a hot, dry spell which threatened late-sown spring rape, reports Dr Kerr Walker of Aberdeen SAC.

Drilling into dust… flax being sown on the Wiltshire Downs last weekend as spring crops throughout the south awaited much-needed rain.