14 June 2002

Keep powdery mildew at bay longer

LONGER lasting powdery mildew protection giving maximum margin over input cost under high disease pressure, but no rust control.

That is what newly approved sugar beet fungicide quinoxyfen offers growers, says maker Dow Agrosciences.

"It does powdery mildew and that is it," admits the firms Rene Pollak. "But powdery mildew is the biggest yield robbing disease in sugar beet."

Across three of Dows own disease-hit trials two 0.2 litre/ha applications of Fortress (quinoxyfen) gave the highest yield response over untreated. In the same work a single application showed more persistent control than the current standard 0.5 litres/ha of Punch C (flusilazole + carbendazim), although that was not reflected in yield.

Despite sulphurs lower cost, £5-6/ha at 10kg/ha compared with £14/ha for 0.2 litres/ha of Fortress or £15-16/ha for Punch C, the double dose of Fortress produced the best margin over input cost, based on an average beet value of £25/t, he maintains.

Mildew control will be important for many this season. "The forecast is that 64% of the national crop will be affected by the end of August, which is one of the highest forecasts we have ever had," comments IACR Brooms Barn plant pathologist Mike Asher.

But he suggests growers continue with tried and tested products for now. "On average we have had nearly 4t/ha response from Punch C in the absence of disease." &#42

QUINOXYFEN FOR BEET

&#8226 Powdery mildew only.

&#8226 Greater persistence claimed.

&#8226 28 day harvest interval.

&#8226 Max total dose 0.4 litres/ha.