Green leaf beet offers frost protection

By Ben Wright

24 August 2011

Sugar beet crops look to have great potential this autumn, with ample soil moisture for root development. But maintaining green leaf will be essential to boost yields and protect roots from frost for later lifting, advises eastern counties agronomist, Richard Palmer.

He warns that the experience of extreme frost damage to roots last year has highlighted the need to retain green leaf for as long as possible; trials have shown good leaf cover can effectively protect crops from two or three heavy frosts. “Our aim is to keep out Rust through the autumn, which will enable the crop to continue to build up yield and root sugar content,” he advises. “Growers need to push yields to ensure they reach quota this season, in order to receive their full entitlement to rebates on seed for next year’s area.”

Mr Palmer advocates growers use a two-spray fungicide programme, with the second spray using Spyrale at the full rate of 1.0 l/ha on all crops planned for lifting more than 28 days after treatment. “Most crops are looking remarkably clean of disease, and the risk of Powdery Mildew should decline as the season progresses. Rust and Ramularia are the key threats in the mild, humid conditions.”

Chris Charnock of Syngenta highlights that Rust, Ramularia and Cercospora have all been identified in untreated plots of sugar beet trials in Lincolnshire. “With the current weather conditions, disease infection will spread rapidly unless controlled. A second spray with Spyrale or Priori Xtra will minimise the effects of any autumn disease attacks and help to boost yields.”

Independent trials have shown a Spyrale two-spray programme delivered an adjusted yield 105 t/ha and a margin over input costs of £340/ha, compared to 96 t/ha and a margin of £185 from a single July application. Two spray programmes have also resulted in significant reductions in Amino N and sodium impurities, compared to a single spray or untreated crops.