14 May 1999

Break crops spray debate

LINSEED and pulses could benefit from a cheap fungicide more than growers believe, says Zeneca pointing to Arable Research Centre trials.

But ARC staff caution that last years apparent benefits from applying Bravocarb (carbendazim + chlorothalonil) came in a very wet season which may not be repeated. More importantly the differences in results in one southern trial were not statistically significant.

"I dont think growers have appreciated just how much linseed and pulse crop yields have been penalised by even low levels of disease," says Zenecas Peter Froggatt.

ARCs northern region manager Christine Lilly confirms that Bravocarb on Oliver winter linseed in mid-May boosted yield by 0.6t/ha (4.8cwt/acre) to lift the gross margin by £69/ha (£28/acre) before area aid. "But in previous seasons we havent always seen yield increases. Its very dependent on the weather after application. Last year the untreated crop had 100% disease, mainly botrytis, by harvest."

A much more important input, she says, is the amount of nitrogen applied to the crop, excess causing lodging and making combining difficult.

A two-spray Bravocarb programme in an ARC trial on peas in Dorset produced a 0.5t/ha (4cwt/acre) yield increase, confirms the firms Tim Mayhew. "But the result wasnt significant," he says. "There is no guarantee of an economic response. But if we were to advise on products it would be Bravocarb because its cheap."