26 January 1996

Winter barley: No PGR needed yet – majority

THIS weeks cold snap should keep winter barleys in check and ease temptations to apply growth regulators, say agronomists.

Although some crops seem very forward, in places reportedly reaching stem elongation (GS30/31), consultants advise against treatment at the moment.

Only Elsoms, UK agent for Gaelic, the early-developing variety which caused much confusion last season, advocates a different approach. "If crops are at the stage at which regulators should be applied, then they should be applied," says the firms Bob Miles.

Return of warm

A return to warm weather will soon push the variety on, he argues. "Were confident it will have had sufficient vernalisation to move into the reproductive phase."

But ADASs John Garstang believes that even where crops have reached GS30 they are likely to remain there for some time. "And you have to bear in mind its the mean growth stage across a field that counts."

"Dummy" first nodes, which develop slowly to produce crown roots, can be misleading, he adds. "Getting to GS30 now is rather like having all your sugar beet lifted at the end of September – you just have to wait!"

Lincs-based Aubourn Farming has a "significant" area of winter barley, including Gaelic. "Its as forward as last year, but no more so," says agronomist Simon Knight. "No regulator policy decision has yet been made. Its definitely not ready for treatment." The Gaelic was purposely drilled later this season, in early-mid October, to avoid repeating 1995 problems, he explains.

Alan Bide of Hampshire Arable Systems warns that mistimed growth regulators can have dual disadvantages. Used too soon on thick crops they may encourage unwanted tillers; and in cold weather sprays may cause "damage" – even where additives are used. He echoes Mr Garstangs views on getting a fully representative picture of field growth stage.

Norfolk-based Colin Myram, of Crop Care Chemicals, believes it is "still far too early" for winter barley regulators even with the adjuvant LI-700. "We need to wait three to four weeks on most sites. On Gaelic wed perhaps go in two weeks time."

Growth stage mainly depends on day length, he adds. And with the coming of Moddus (trinexapac-ethyl) growers have "a bit more flexibility" over timings this spring.