2 June 1995

Approval for growth regulator phased out

APPROVAL for using a well-known growth regulator on spring barley is being phased out because it serves no useful purpose, according to the Pesticide Safety Directorate.

PSD says trials, mainly at the Scottish Agricultural Colleges and ADAS, have shown "no consistent benefit" from using chlormequat on the crop. So approvals for all "chlormequat only" products are being revoked.

The move comes as no great surprise, says Lance Middleton, spokesman for one of the main suppliers, BASF. Only very small amounts are used on spring varieties. "Id guess about 10% of Scottish spring barleys are treated, but the English area is very small.

"There may be a benefit by manipulating tiller numbers, but its unreliable," he says.

Dr David Cranstoun, cereals specialist at the SAC, doubts the 10% coverage figure even north of the border. "There wont be a lot of disappointed Scottish growers." Most spring varieties are "pretty stiff", he adds.

&#8226 Growers waiting to apply wheat flag-leaf fungicide sprays still have time to apply Terpal (ethephon) to guard against lodging, says BASF. Many growers are said to be unaware that the late regulator may be mixed with all the main azole fungicides. It should not be used after ear emergence.