26 December 1997

Match spray to variety – plea

FARMERS are throwing money away on unnecessary fungicide treatments because they ignore differences in varietal resistance

"I am shattered by the national picture," says Doug Stevens of Morley Research Centre. "Growers are not following our advice. Although they take disease resistance into account when choosing a variety they seem to forget about it later on."

Riband and Brigadier need a comprehensive fungicide programme, because they can lose almost a quarter of potential yield from Septoria tritici if left untreated, he notes. But losses in Hereward and Haven are typically half that figure.

Despite that a MAFF survey of over 1200 wheat crops between 1994 and 1996 showed little difference in the way varieties are managed, he says.

"Resistant Hunter received similar fungicide treatment to the much more susceptible Riband. Hereward, the least responsive variety in the survey, received more inputs than all other varieties examined, except Brigadier." Even when quality protection is taken into account that is excessive, says Mr Stevens.

Work carried out from 1994 to 1996 by ADAS and Morley shows 0.7 litres/ha is the optimum dose for Riband and Brigadier when using tebuconazole (Folicur). For Hussar, it is just 0.4 litres/ha. "The difference is even greater for a more usual two or three spray programme."

Growers could easily save £10m a year, he reckons.